When President Carter announced his anit-inflation guidelines last fall, construction wages appeared to be the least of his worries.

But now the government is feeling the first twinges of another hard-hat headache.

Soaring construction wages had been a key factor in the inflationary surge of the early 1970s, but intense non-union competition and other forces gradually deflated the annual rate of construction contract increases to between 6 and 6 1/2 percent - well within Carter's 7 percent ceiling.

Early 1979 forecasts indicated that this relatively moderate rate of increase, sunstantially below the 10 percent-plus settlements for many big industrial unions, was likely to continue this year.

But it hasn't, at least in the first wave of contract settlements that are being reported by industry groups.

"They're high and I'll surprised if they don't go higher," said Dennis M. Bradshaw, president of the Washington-based Contractors Mutual Association, which monitors wage settlements for the unionized sector of the nation's $200 billion a year construction industry.

Of about 100 settlements reported thus far this year to CMA, the average increase in wages and benefits is 8.6 percent, according to Bradshaw.

While these contracts represent less than 10 percent of the 1,200 contracts expected to be negotiated this year, Bradshaw said he doesn't expect any abatement in the rate of increase as bargaining extends into the summer.

Bradshaw blames rising prices and the Carter administration's bending of the 7 percent guideline to accommodate a Teamster settlement of roughly 9 percent a year, or 30 percent compounded over three years, for the unexpected guideline-busting by the building trades unions.

"There are people who could have settled within the guidelines in January who are not doing so now," he said in an interview last week. "Even when they (union and company bargainers) started not far apart, they're settling on the high side."

Bradshaw said he feels administration inflation fighters are underestimating the impact of escalating construction settlement in their concentration on big industrywide contracts like the Teamsters' master freight agreement.

He said the government seems to be relying exvessively on the steady growth of non-unionn construction to keep the building trades unions from exvessive wage demands but asserted that this doesn't work when there are enough jobs for everyone, as is currently the case in many areas.

He cited the case of Houston, where business is booming and settlements thus far this year range from 8.8 to 10.7 precent a year, according to a recent compilation by the Houston Business Round-table.

In a protest letter to the Council on Wage and Price Stability, the Government'd inflation monitoring agency, the group complained that non-union wages, which are being kept within the guidelines, will increasingly be subjected to "catch-up pressures" and thus help fuel inflation in the future.

Bradshaw also cited the case of sheet-metal workers in Portland, Ore., who, he said, recently won hourly increases of $2.25 a year on top of an hourly wage base of more than $13.

Another source close to the construction industry, acting independently of Bradshaw, also monitored about 100 contracts and came up with an overall average of 8.5 precent. But he thinks the rate of increase will level off at about 8 percent for the year - less than now but still well above last yera's level and the guideline goal.

"Both the (union) leadership and rank-and-file are bullish," said the construction expert, who asked not to be identified. "They feel they've been lagging behind and now's the time to catch up."