A group closely allied with New York Gov. Andrew M. Cuomo received $2 million from gambling interests last December as he developed a proposal to expand casino gambling in the state.

Cuomo's support for expanded gambling, which he made a centerpiece of his State of the State address in January, had a profound impact. Within weeks, the Legislature endorsed a constitutional amendment that, if approved once more by lawmakers and then by voters, would allow for seven full-scale, privately owned casinos, potentially worth billions of dollars.

The contributions went to the Committee to Save New York, a business and labor coalition that raised $17 million and spent nearly $12 million in 2011, much of it on campaign-style television and radio advertisements praising Cuomo and advocating for his proposals to cap property taxes and slash state spending.

The New York Gaming Association, a trade group founded by Genting and other companies that operate racetracks and electronic slot machines, chipped in $2 million to the committee. Genting, a subsidiary of Southeast Asia's largest gambling company, gave an additional $400,000 to the group allied with Cuomo during 2011.

Founded by real estate developers and business executives at Cuomo's urging shortly after he was elected governor, the Committee to Save New York has rapidly become the biggest spender on lobbying in Albany, providing not only critical backing for Cuomo but also a counterweight to the labor unions whose money and political muscle have traditionally dominated the Capitol.

Cuomo, a Democrat, strongly disputed any suggestion that he was influenced by money from the gambling industry. He noted that he had expressed support for an expansion of casino gambling months before the contributions were made, and that he had diverged from the gaming association on several key issues.

“To try to suggest an improper relationship between the governor and gaming interests is to distort the facts in a malicious or reckless manner,” Richard Bamberger, a spokesman for the governor, said in an email.

The Committee to Save New York defended its fast-growing role in Albany.

“From the inception of CSNY, we have focused on a reform agenda designed to help create jobs, improve the economy of our state and get state government working for the people again,” said Michael McKeon, a spokesman for the committee. “We are proud of our track record, and if there are people who felt they were getting something more for contributing to CSNY, then they are simply wrong.”

Because it is organized as a nonprofit social advocacy group, called a 501©4, the Committee to Save New York is not required to disclose the sources of its money publicly. But The New York Times learned some details of the group's financing through a review of public records and interviews with more than two dozen individuals familiar with the group's activities.

The $2 million from the gaming association appears to have been the committee's second largest contribution in 2011, according to a tax return released by the committee last month, which included information on donation amounts but did not identify donors.

The group's single largest donor was another business advocacy organization, the Partnership for New York City, which gave just over $3 million.

Two companies that belong to the Partnership for New York City also contributed to the Committee to Save New York: Citigroup and JPMorgan Chase, each of which contributed $25,000.