New York Gov. Hugh L. Carey accepted today the resignation of the chairman of the agency that watches over New York City Finances and borrows money for the city, then asked the agency's previous chairman, Felix Rohatyn, to return on a temporary basis.

Rohatyn, a partner in the investment banking firm of Lazard Freres, told Carey he would decide by Monday.

Earlier today, George Gould, who had taken over chairmanship of the Municipal Assistance Corp. last January, told Carey he wanted to resign the unsalaried post in June 10, Gould also resigned his position as head of the state financing agency.

Carey at first asked Gould to reconsider, but later accepted the resignation. Gould, who had been a member of the Municipal Assistance Corp. board since it inception in 1975 and chairman of the housing agency for 2 1/2 years, said he had to return full time to his post as president of the Madison Fund, a mutual fund that manages $450 million in stocks for 66,000 investors.

The Municipal Assistance Corp. was set up when New York City neared bankruptcy in 1975. It monitors the city's spending and uses the borrowing powers of the state to sell securities to raise funds for New York City. MAC plans to sell $125 million in long-term bonds next week.

After Rohatyn retired from the post as chairman in January, Lazard Freres asked for $250,000 to act as an adviser to MAC, which it done for free when Rohatyn was head of MAC.

After Lazard was criticized by New York Mayor Edward Koch, saying taking the fee was in "moral conflict of interest," the investment banking firm resigned its consultant role.