ALBANY — One of three remaining dissidents in the Democrats’ newly won Senate majority said Monday he won’t support Sen. Malcolm Smith as majority leader because that could lead to legalizing gay marriage.

But Sen. Ruben Diaz Sr. said in a statement after one of the other so-called “Gang of Four” broke ranks and backed Smith that he will remain with the Democrats.

That further erodes Republican chances of regaining some power through the dissidents. Smith, the current minority leader, gained support Saturday from one of the four, Sen.-elect Hiram Monserrate of Queens. Smith is backed by most of the conference he led to a 32-30 seat advantage in last week’s elections, which set the stage for the first Democratic majority in more than 40 years come Jan. 1.

“The top priority for Senate Democrats is to get New York’s economy working again,” said Smith’s spokeswoman, Juanita Scarlett. “Senator Smith has said he will govern by the consensus of his conference. He has vowed to reform the rules of the state Senate, allowing proposed legislation to be debated on the Senate floor, even legislation he does not personally support.”

There isn’t a clear consensus on gay marriage among the Democrats in the Senate, where the Republican majority has long blocked the measure. The other renegade Democrats are Pedro Espada Jr. of the Bronx and Carl Kruger of Brooklyn. Their power play last week, which included demands for a stronger Latino voice in the conference, boosted their chances of getting committee chairmanships that come with lucrative stipends, far greater attention from lobbyists and campaign donors and the power to steer legislation.

“I have not committed myself to anybody, and my position as an ordained minister and a pastor will not allow me to support any would-be leader that will bring gay marriage to the Senate floor,” Diaz said. Diaz said the dissidents have a handshake commitment to meet Tuesday and then make a public announcement. Diaz, however, said he won’t sit with the Republicans.

“Where is it written that if you do not support gay marriage you are not a good Democrat? I have always been a Democrat,” Diaz said. “I remain a Democrat, and I will continue to be a Democrat. A Democrat who rejects gay marriage and abortion based upon my beliefs.”