ALBANY – Democrats in the state Senate flexed their legislative muscle yesterday in one of the few ways they are able, delaying a vote on budget-related legislation that would have required a two-thirds majority to pass.

The Republican-led Senate and the Democratic-led Assembly have passed legislation in two consecutive sessions aimed at putting the issue of budget-related changes to the state constitution before the voters in a statewide referendum this November. The passage of those bills ensures that the referendum will take place this fall.

However, a companion bill that would have to be passed to allow constitutional changes to be implemented has yet to be approved by lawmakers following vetoes last year and this week by Governor Pataki. It was a vote to override Mr. Pataki’s veto of this so-called enabling legislation that Democrats in the Senate chose to delay yesterday.

The constitutional changes being sought include moving the date of the budget deadline to May 1 from April 1 and establishing a provision that would put a contingency budget in place when the deadline is not met. Legislators said the changes would ensure that budgets are passed on time every year.

Under another, more contentious provision, the budget bills submitted by the governor to the Legislature would become invalid at the budget deadline. Opponents of the amendment focus on this proposed change, saying it would effectively reverse the balance of power to the Legislature from the executive branch after the May 1 deadline.

The most prominent opponent to step forward is the state attorney general, Eliot Spitzer. Mr. Spitzer is the presumptive Democratic nominee for governor in 2006 and is thought to oppose the referendum because it could greatly reduce the powers of the office to which he aspires.

Mr. Spitzer has declined to comment on that aspect of the change, however, limiting his criticisms to the process by which lawmakers are seeking a change.

A delay on the override vote by Democrats, who have until now supported the amendment by wide majorities, caused some in Albany to wonder whether legislators are beginning to line up behind the man they expect to replace Mr. Pataki. The minority leader of the Senate, David Paterson, a Democrat of New York City, declined to comment on the decision to delay the vote.

The majority leader of the Senate, Joseph Bruno, a Republican of Rensselaer, downplayed the delay. He said yesterday afternoon he was confident the votes would be there and that Democrats simply needed more time to think about the proposed changes.

“They needed review and they needed to talk about it, and it sort of was moving rather quickly, and I could understand their concern that they just wanted to have time to discuss among themselves,” he said.