Republican gubernatorial hopeful Rick Lazio gained his most influential upstate endorsement so far and the first from Western New York when Mike Norris, the new chairman of the Niagara County Republican Party, declared his support Monday for the former Long Island congressman.

Norris, who recently succeed Henry F. Wojtaszek as chairman, officially cast his lot with Lazio during the party’s holiday gathering in the Lockport Holiday Inn.

Norris took the step in the backyard of Erie County Executive Chris Collins, who also is considering a run for governor but is not expected to decide until next month. That prompted James P. Domagalski, chairman of the Erie County Republican Party and a Collins ally, to question the timing.

“I certainly respect Chairman Norris and his right to make an endorsement, but it’s a little premature,” Domagalski said late Monday. “Rick Lazio is the only announced person in the race. In any good process, you’ve got to look at all potential candidates.”

But Norris emphasized he wants to begin the process immediately.

“The people of Niagara County and throughout this state are looking for someone who will deliver fundamental change to New York, and Rick Lazio is that person,” he said. “Most importantly, we need someone who will create jobs in Western New York. I believe the person who can best do that as governor is Rick Lazio.”

Lazio, who ran unsuccessfully against Hillary Rodham Clinton for the Senate in 2000, has been an official candidate for months. During that time, he has picked up official endorsements from party chairmen in Suffolk, Schoharie and Orange counties. He also has been no stranger to Western New York.

His stature as a candidate for governor has grown in recent weeks amid indications that former New York City Mayor Rudy Giuliani is leaning against running and after Collins’ setback from remarks comparing Assembly Speaker Sheldon Silver — an Orthodox Jew — to Hitler and an Antichrist.

Lazio said Monday he considers Western New York support crucial to his campaign.

“It is critically important that Western New York achieves its full potential if we are to be the Empire State once again,” he said. “I believe that Albany’s relationship with Western New York should be that of a partner, not a master.

“With Niagara County on board, we’re making great strides towards victory in November,” he added.