Cabinet-level nominees to President-elect Jimmy Carter's administration have assured the nation's mayors federal urban programs wll continue, mayors said yesterday.

"We are talking about how much and not about whether or not," Detroit Mayor Coleman Yougn said at the conclusion of a two-days meeting of the U.S. Conference of Mayros here.

"Firm commitments" were obtained, he said.

"We have every reason to believe that this is the beginning of a new relationship between the White House and the nation's mayors," said Kenneth Gibson, mayor of Newark, N.J., and president of the Mayors' conference.

Eight nominees for Carter's Cabinet and two top advisers met with mayors attending the organization's 45th annual midwinter gathering.

Gibson said Carter Cabinet appointees told mayors they would "be consulted before - and not after - executive decisions have been made."

Mayors were "extemely disappointed." Gibson said, that spending plans fall short of the conference goal of a $12.3 billion national urban investment program.

"We are committed to a $12.3 billion spending program and we intend to lobby for it." Gibson told reporters.

Carter, much like the Ford administration, does not plan to commit enough money to cities to satisfy the need for federal assistance, Gibson said.

The budget submitted to Congress Monday by President Ford was "glaringly deficent" and showed "a major disregard for the needs of urban America," Gibson said.

Mayors attending the meeting on the eve of Carter's inauguration expressed satisfaction with Carter's Cabinet appointments. Gibson said it was "unprecedented" for nominees to meet with the mayors before confirmation.