ALBANY, N.Y. – Less than a week before thousands of sex offenders were to begin falling off the public registry that tracks their whereabouts, the state Legislature reached an agreement to extend the law that lists them.

Under the proposed agreement, the most violent offenders would have lifetime registration in the Megan’s Law database, with level two offenders able to petition to be taken off the list after 30 years.

The lowest level offenders would be registered for 20 years.

The state Assembly and Senate were to review the proposal yesterday, with passage expected today.

Governor Pataki said he needed to see the details of the agreement, but called it “a very positive step forward.” Mr. Pataki also said he was disappointed the deal didn’t include lifetime registration for the lowest level offenders, but did say the agreement was an improvement.

“We agree with the intent … it strengthens the law,” Mr. Pataki said.

The deal would need Mr. Pataki’s approval to expedite passage today.

The current law, set to expire Saturday, requires the lowest level offenders to be listed for 10 years.

If the law had not been renewed, more than 3,500 sex offenders in New York were expected to fall off the list by the end of the year.

“The specter of individuals going off the list this weekend is removed,” said Assemblyman Jeffrion Aubry, a Democrat of Queens.

There are more than 21,000 registered sex offenders in New York state.

State Senator Jeff Klein, a Democrat from Westchester, said in a statement the compromise was “a defeat” for New Yorkers.

The agreement failed to require an option for free e-mail updates on the most violent offenders, he said.

The Republican-controlled Senate previously argued for lifetime registration of all sex offenders, while the Democrat-controlled Assembly was seeking a temporary fix until Congress set a standard for a national database.