The hiring of thousands of temporary census workers helped push the nation's unemployment rate down slightly to 5.3 percent in May, the government said yesterday.

However, analysts viewed the 0.1 percentage point decline in the nation's jobless rate as a sign of a sluggish economy because private sector job growth slowed to a near standstill.

''These numbers are a real danger signal ... and bring into question whether we can muddle through without tilting toward recession,'' said economist David Jones of Aubrey G. Lanston & Co.

The report, the first comprehensive look at May's economic activity, shows the economy is ''worse than sluggish -- it is moribund,'' said Richard W. Rahn, chief economist at the U.S. Chamber of Commerce.

In other economic news yesterday, the Commerce Department reported that construction spending continued to slide in April, dropping 0.7 percent for the second straight month as interest rates remained high.

The civilian jobless rate as measured by a household survey fell slightly in May from April's 5.4 percent unemployment rate, the Labor Department said. The nation's jobless rate has been fluctuating around 5.3 percent for more than a year.

There were 164,000 new jobs created last month, according to a separate survey of business establishments, but the number was artificially inflated by the federal government's hiring of 145,000 temporary census workers.

Since February, the economy has added just 264,000 new jobs, and if government jobs are excluded, private payrolls actually decreased by 105,000, the government said.

In a private-sector survey, the nation's purchasing managers indicated that there has been an improvement in manufacturing performance in May, but economists said the report was overshadowed and contradicted by government unemployment numbers.

Gains in production and new orders led the increase, the second in as many months for the purchasing managers' index.

Employment in the nation's manufacturing sector, which has been in a slump for months, continued to falter as factory jobs decreased by 35,000, bringing the total manufacturing losses to 310,000 jobs since March 1989. The electrical equipment, auto and apparel industries together have lost 190,000 jobs during that period.

Construction jobs fell by 20,000 in May, reflecting continued weakness in the housing market, the government said.

James Solloway, director of economic research at Argus Research Inc. in New York, said the rise in the purchasing manager's index is more a sign that the manufacturing slump has hit bottom than it is a precursor of a strong recovery.

''It does show some stability in manufacturing coming in. But things are still soft,'' Solloway said.