The state Board of Regents voted this week to reduce the mandatory school age to five and to require that all school districts offer full-day kindergarten classes. It also voted to make pre-kindergarten available to all 3- and 4-year-olds.

The policy changes must next win the approval of state lawmakers, who have already started voicing some concerns.

The chairman of the state senate’s Education Committee, Stephen Saland, said he was “troubled” by the idea of mandating full-day kindergarten and worried about coming up with funding.

“I am troubled not only because the Regents don’t provide the funding for this proposal, which statewide would cost several hundred millions dollars, but they really haven’t demonstrated that the existence of half-day kindergarten is detrimental to a child’s education,” Mr. Saland said.

Currently, 79 districts do not offer full-day programs; most are in suburban areas.

The state Department of Education estimates that an additional 13,000 children would enroll in kindergarten classes if the policy passes in Albany.

Parents would be able to seek a waiver if they wanted to keep their child out of school until age 6.

The Regents are asking for $280 million to construct about 850 new kindergarten classrooms, including 100 in the city.

The full-day kindergarten classes would be phased in over three years and cost an additional $2.8 million starting in the 2006-07 school year, a number that would grow to $62.1 million in 2010.

The Regents did not say how much the pre-kindergarten component would cost.

Early-childhood education advocates who have been pushing for the changes for years lauded the Regents for approving the policy.

The president of the Schulyer Center for Analysis and Advocacy in Albany, Karen Schimke, called the policy an important step for boosting student performance in later years.

“The education system is struggling to have kids ready to move through their learning days and succeed,” she said. “Kindergarten is central to that, and pre-kindergarten is central to that.”

The state spends about $200 million on pre-kindergarten classes for 72,000 of the state’s 240,000 4-year-olds.

The veteran chairman of the Assembly’s Education Committee, Steven Sanders, who recently retired, said he expects the kindergarten portion of the policy to easily pass through both houses.

He said the costs would be offset by other savings, because children would be more likely to succeed if they started school at a younger age.