ALBANY – The work habits of two state lawmakers from New York City are becoming an issue in their re-election campaigns as challengers ask why they were absent for so many votes at the state Capitol.

Senator Olga Mendez of East Harlem, a Democrat-turned-Republican involved in a hotly contested race, missed 27 of 131 session days over the past two years, the most of any senator.

Mrs. Mendez, who is 79, said her health-related absences have not prevented her from being an effective representative of her district. But a Democratic challenger, Council Member Jose Serrano, argues that “half the job is showing up.”

In Greenwich Village, meanwhile, Senator Thomas Duane, a Democrat, faces criticism for skipping three weeks of the legislative session, in late January and February, to take a class at Harvard University’s Kennedy School of Government. In all, he missed 21 days in the past two years, the second most of any senator.

“We’re paying for him to represent us in Albany, not to go to school in Boston,” said his Republican opponent, Emily Csendes.

The absentee rates of both senators were high enough to put them in the top 10 of the 212-member Legislature, according to an analysis of official attendance records for 2003 and 2004 by The New York Sun.

Most members with high absentee rates are either struggling with a serious illness or caring for a sick family member. Heading the list was Assemblywoman Nettie Mayersohn of Queens, who has missed 29% of the Assembly’s meetings since her husband underwent a heart bypass operation.

Ms. Mayersohn said she has been able to keep up with her duties by phone. “When I get a message that we have a serious vote taking place, I’m there,” she said.

After her was Assemblywoman Sandra Lee Wirth of western New York, who missed fully half of this year’s session after being diagnosed with cancer; Assemblyman Anthony Seminerio of Queens, who underwent a triple heart bypass last year, and Assemblyman Vito Lopez of Brooklyn, who was diagnosed with leukemia in 1993.

Also on the list was Assemblyman Daniel Hooker of Schoharie County, who has a unique excuse for missing 10 session days last year: A major in the Marine Corps Reserve, he was called to active duty in America during the war in Iraq.

Legislators do not have a fixed allotment of vacation or sick days. As independently elected officials, they set their own schedules and answer to no one but the voters of their districts. They collect their full salaries of $79,500 – plus, in most cases, a stipend for leadership duties – regardless of how many days they appear at the office.

Most of the lawmakers with low attendance at Albany do not face serious challenges for re-election in November. Ms. Mayersohn, for example, has no opponent, and Mr. Seminerio, a Democrat, has been endorsed by the Republican, Conservative, and Independence parties. Mr. Duane, too, has to be considered the odds-on favorite in his heavily Democratic district. He outpolled his last Republican opponent by a ratio of 4-1.

Mrs. Mendez is the exception. A lifelong Democrat who was first elected in 1978, she joined the Senate’s Republican majority shortly after the 2002 election. Her perceived vulnerability in a predominantly Democratic district has drawn two well-known challengers into the race – Mr. Serrano, who is the son of Rep. Jose Serrano, and Nelson Denis, a former assemblyman, who are competing in a Democratic primary on September 14.

Last week, Mr. Serrano said he plans to contrast his own near-perfect attendance at council meetings with the

higher absenteeism rates of both Mrs. Mendez and Mr. Denis.

“I firmly believe that you can’t properly do your job unless you show up, you’re present,” he said. “It sends a very strong message to the constituents that elected you, that you’re there to do hard work…. I’m very happy to come to work. I love my job. I couldn’t fathom missing large amounts of hearings and meetings.”

Mrs. Mendez rejected this criticism.

“My absenteeism…has not affected my productivity,” she said. “My office has been running well, I have a good staff, and I have taken care of my constituents’ concerns….

“I would not run if I would feel that because of whatever reason – health or whatever -I would not be able to do the job, because my constituents have been so good to me.”

Mrs. Mendez, a survivor of breast cancer, said she has recently been undergoing treatment for arthritis and is due to undergo surgery for polyps on her vocal chords in the next few weeks. She said she considered retiring from the Senate earlier this year, but changed her mind after consulting with her doctors.

“I am in very good health for my age and – you know what? – I enjoy my work,” she said.

Mrs. Mendez charged that the diligent attendance of Mr. Serrano, who is 32, had not resulted in much of substance for his district.

“What matters is the product,” she said. “What in the world have you achieved in three years in the City Council?… He’s entitled to run, but I feel sorry for my constituents if he gets elected.”

Mrs. Mendez was the chief sponsor of 16 bills that passed both houses of the Legislature this year, which was about average among her Republican colleagues. The most important of her bills provided for a $2 increase in the minimum wage, to $7.15 an hour from $5.15 an hour. It was vetoed by Governor Pataki, and the Senate is debating whether to override him.

On the 16 days she was absent this year, between January and April, the Senate approved 201 pieces of legislation, including 30 that ultimately passed both houses and went to the governor. It’s unlikely her vote would have made much difference in the outcome. Under the centralized leadership system that prevails in the Legislature, no bill comes to the floor of either house unless it is guaranteed of passage.

Still, the legislative director of the New York Public Interest Research Group, Blair Horner, said it is important for lawmakers to be in Albany – to debate issues, buttonhole their colleagues, and meet with constituents and interest groups.

“It’s hard to be represented in a democracy if your representative isn’t there,” Mr. Horner said. “They may not care. They might say, ‘We still want to have Olga there even though she’s only there 80% of the time.’ But that’s a legitimate thing for people to consider.”

An aide to Mr. Duane, Mark Furnish, said the senator considered the class at Harvard to be a “positive experience” that will help him in his work as a legislator. Mr. Duane also missed some session days to take care of a sick relative, Mr. Furnish said.

“This is an aberration this year with those two things,” Mr. Furnish said. “Usually he’s pretty good.”

Ms. Csendes questioned why Mr. Duane didn’t find a class that met later in the year, after the regularly scheduled legislative session. “It’s definitely an example of his lack of accomplishments and his lack of true representation for New Yorkers,” she said.