Labor Secretary Ray Marshall said yesterday he expects the nation's 7.1 per cent unemployment rate to "stay pretty close to where it is" for the time being, and then to "gradually decline in the coming months."

Marshall's muted expression of optimism came two days after his department released figures showing a national rise in unemployment from 6.9 per cent to 7.1 cent last month - with the highest unemployment among blacks, whose rate rose from 13.2 per cent to 14.5 per cent.

The Labor Secretary said he expects the rate to decline gradually because much of the unemployment reflected in the latest figures "is due to the rise in unemployment among teenagers and young people".

Many young people are expected to drop out of the labor market as they return to school this fall, thus reducing the number of people actively looking for work.

Marshall also noted in an interview on "Face the Nation" (CBS, WTOP) that President Carter's two-year jobs and economic stimulus program "has not yet started having its effect."

"It [the stimulus program] will have a substantial effect during the last quarter of this year when approximately $13 billion will be expended, and in fiscal year 1978, when $21 billion will be expended," Marshall said.

He added: "We think that this will do some things to cause unemployment to decline in the coming months. We think it's also important to continue on the course of trying to stimulate business and consumer confidence will rise.

"This is the key to the [economic] recovery that we see right now," Marshall said.

The Labor Secretary was asked if he thought the black unemployment rate could be interpreted as a "betrayal" of blacks on the part of President Carter, who received crucial black support in the presidential election.

"I don't think it's a betrayal of black support," Marshall replied. "Much of what we will do to affect youth unemployment in general and black unemployment, in particular, still remains to be done," he said.

Marshall said he believes the administration "owes the black community significant attention - not necessarily because of [black] political support, but because there's a special need".