On the eve of a vote by AFSCME that is expected to kill a tentative union concession plan, a top adviser to Gov. Dannel P. Malloy said the administration might be open to a new vote by the bargaining units that voted it down, but it won’t offer new terms.

Union spokesmen called the question of reconsideration premature while some bargaining units are still voting. Eight of the 15 state employee unions have ratified the agreement, one has rejected it and six others will finish voting Friday. With voting complete by eight of its nine bargaining units, ratification by AFSCME is unlikely.

“Any discussions about steps that would be taken prospectively will happen once the vote’s completed,” said Larry Dorman, a spokesman for AFSCME. “That’s the most I can say at this point. We clearly have heard from members that are not happy about some of the voting that has taken place.”

Malloy’s senior adviser, Roy Occhiogrosso, said the governor remains adamant that the tentative deal will not be renegotiated. However, he said the administration might be willing to clarify the terms of the agreement now on the table.

“Clarifying and renegotiating are two different things,” he said.

If the agreement is rejected, the governor will submit a plan to the General Assembly to close a $1.6 billion gap that would left in the $40 billion biennial budget that takes effect July 1, Occhiogrosso said.

“Spending cuts, layoffs, cuts in municipal aid, those are all options,” Occhiogrosso said. “The only thing that’s not an option is a tax increase beyond what’s already been agreed to.”

Malloy, who was at a meeting in Washington today, returned to tell his advisers in a late afternoon meeting at the Executive Residence that he wants a revised budget that spares municipalities as much as possible.

Senate Minority Leader John P. McKinney, R-Fairfield, said Republicans would try to raise collective bargaining changes at any special session, seeking a vote to eliminate longevity payments and explore whether retirement rules could be change to bar overtime pay from pension calculations.

“We will talk about that,” McKinney said. “I would like to talk to the majority about some of these structural changes. I am not being naïve. They are very difficult to do politically. They are also difficult to do legally.”

The GOP leader said he hoped the apparent failure of the concession would be a catalyst for Democrats to consider changes in collective bargaining laws.

Senate President Pro Tempore Donald E. Williams Jr., D-Brooklyn, had no comment on the status of the concession deal.

With AFSCME on the verge of voting down the tentative labor concession agreement, another of the 15 unions in the State Employees Bargaining Agent Coalition also has rejected the deal, a blow to a plan to resolve the budget crisis without layoffs. Two more more ratified it Wednesday.

The Connecticut Employees Union Independent, representing about 4,500 service and maintenance workers,  voted Tuesday to reject the deal, but its results were not confirmed until today, when two unions representing faculty at the UConn Health Center and in the Connecticut State University system overwhelmingly voted yes.

The tentative deal reached a month ago with the Malloy administration is faltering even as it becomes clear that a majority of state unionized state employees favor ratification.

“There are enough results confirmed by individual unions that we can say a majority of state workers have approved the agreement,” said Matt O’Connor, a spokesman for the union coalition. He made that statement before the UConn and CSU votes.

But under the coalition’s rules, ratification requires two things: passage by 14 of the 15 unions; and the unions voting in favor must represent at least 80 percent of state employee union members.

It appears the coalition will fall short of both measures.

AFSCME, which represents about one-third of unionized state employees, is poised to vote down the agreement. With all but one of nine AFSCME bargaining units having voted, ratification is badly trailing. A no vote by AFSCME is enough to kill the deal, since the other unions would fall short of 80 percent.

Eight of the 15 unions have ratified the agreement, as have a majority of the 34 bargaining units within those unions. The remaining units vote today, Thursday and Friday.

“There are ballots not yet cast, which is why we don’t want to talk about the final outcome,” O’Connor said.

He said passage still was a mathematical possibility, then conceded that so was his chance at hitting the lottery.

For AFSCME to ratify the tentative agreement, a local representing correction officers would have to pass it by a landslide. Correction officers in two other AFSCME locals within the same bargaining unit have rejected it by more than a 2-1 margin.

Local 391, the last AFSCME members to vote, represents employees at six prisons. Its members vote Wednesday and Thursday, but results might not be available until Friday morning.

The eight unions to vote yes:

• New England Health Care Employees Union, District 1199/SEIU, representing 7,700 nurses, doctors, social workers, technicians and others in a various of agencies and facilities, including the UConn Health Center.
• AAUP at the University of Connecticut, representing 2,000 faculty and researchers at the main campus in Storrs and regional campuses in West Hartford, Waterbury, Torrington, Stamford and Avery Point.
• Connecticut Association of Prosecutors, representing 260 state prosecutors.

• Connecticut Federation of School Administrators, representing 61 principals and others at 18 vocational technical high schools.
• Connecticut Police and Fire union, representing about 900 public-safety personnel across state government, with the exception of state police officers.
• AFT Connecticut, representing 6,800 employees in higher education, health care, vocational education and other areas.
• AAUP in the Connecticut State University system, representing 1,150 faculty, counselors and others.
• AAUP at the UConn Health Center, representing 550 faculty.

The union voting no:

• Connecticut Employees Union Independent, representing 4,500 maintenance and service employees.

The six unions yet to vote or report:

• AFSCME Council 4, represent 15,600 employees across state government.
• CSEA/SEIU Local 2001, representing 3,900 workers, ranging from bridge inspectors to state police supervisors.
• Administrative & Residual Union, representing 3,300 state administrative workers.
• Congress of Community Colleges, representing 2,000 faculty and professional staff.
• Connecticut State Police Union, representing 1,150 troopers sergeants and master sergeants.
• IBPO/SEIU Local 731, representing 750 judicial marshals.