Sen. Gary W. Hart (D-Colo.) said yesterday a split is developing between "newer leaders of the Democratic Party" like himself and New Deal liberals whose economic proposals "are just the same old things."

"If we see any change in the party, I think it is between those who have espoused the traditional New Deal approaches to social problems and economic problems, as opposed to those . . . who are attempting to question some of the premises upon which the Democratic Party has operated.

"I think that is where the division is coming," Hart said on "Meet the Press" (NBC, WRC).

The 39-year-old senator, who headed Sen. George McGovern's 1972 presidential campaign, said he disagrees with McGovern's recent charges that President Carter is sacrificing welfare reform and other social programs in pursuit of a balanced budget.

McGovern's view "assumes that certain positions are traditionally Democratic and traditionally liberal," Hart said. "Those [are] positions I have been trying to call into question as have other newer leaders in the Democratic Party."

Hart added, "President Carter had campaigned on a platform of a balanced budget, and I don't think it is fair to fault him after he is in office for trying to achieve that." He said he believes "the jury is still out on the Carter administration."

Hart said he and other younger party leaders - made skeptical by the Republicans' Watergate and the failure of many Democratic social programs - "are questioning whether government in fact can solve all the problems."

"At the same time, I think we are trying to redefine what the role of government should be," he said.

"I think the problem is that both parties have sort of run out of ideas," Hart said. "I think it is incumbent upon the Democratic Party to come up with some new proposals to question the structures of our economy - the tax system, the welfare system, the monetary system . . . to come up with some new economic tools instead of just the same old thing."