Every three years there is a pause in the noisy clanking of the nation's collective bargaining machinery when no big pacesetting contracts come up for renegotiation. This is one of those slow years.

But that doesn't mean there will be much of a wage slowdown in 1978, according to economists and goverment inflation, fighters who predict continued escalation of labor costs this year.

A major reason is that labor contracts have become anti-inflation, anti-unemployment insurance policies - loaded with deferred wage-benefit increases, cost-of-living escalartors and expensive job and income security gurantees to protect workers against future vicissitudues of the economy.

Continued high unemployment, coupled with competition from non-union workers, is expected to keep a damper on wages in construction, which accounts for more than one-third of workers convered by expiring contracts, an unusually high proportion.

But built-in increases from previously negotiated contracts, along with new contracts fashioned with those increases in mind, are expected to keep wage-benefit hikes from falling much below their current 8 to 9 per cent level.

"Collective bargaining is on automatic pilot for the year," said ecomoist Arnold R. Weber, chairman of a Conference Board panel that recently predicted wage-benefit increase ranging from 7.5 to 10 per cent for the year.

"I don't see anything on the horizon that can break that pattern," said Audrey Freedman, senior labor relations associate for the board, a New York-based business research organization. "There may be some gradual mitigation of the cost pressure because of the nature of the labor market involved this year [the relatively competitive construction and service industries], but it won't be much of a contraction," Freedman said.

The board predicted an overall labor cost increase, per unit of production, of 5.8 per cent, down slightly from the 6.7 per cent level as of last October.

The board's general assessment is in line with projections by the governemt's Council on Wage and Price Stability, although the council sees a danger sign that could point the way to an even higher rate of increase for 1978 and beyond.

A generally anticipated increase in construction activity could lead to pressure for higher wages, said Sean sullivan, who is preparing a report for the council on the collective bargaining cutlook for 1978. Since the rate of construction wage increase plummeted in the mid-1970s, construction has been a moderating influence on wages. But if construction wage escalation starts up again, it could set the stage for a bigger wage push when the next round of major industrial bargaining opens in 1979, according to Sullivan.

"Construction may become a culprit again this year, although it's been a good guy for several year," Sullivan said.

Another uncertainty is a pair of bargaining holdovers from 1977: rails and coal.

Works rules are the main sticking point in the rail negotiations, but economists expect the more settlements to be within the 10 per cent annual range won over the last two years by other major industrial unions. And the later the settlement comes, the greater the potential impact on the 1979 big industry talks involving such giants as autos and trucking, some economists suggest.

Coal is, as usual, a puzzlement. In the strike begun Dec. 6 by the United Mine Workers, wages are less an issue than benefit guarantees and grievance machinery (for the union) and workforce stabilitty and productivity (for the operators).

But some observers believe the industry might trade off a generous money package for an end to wildcat strikes and other threats to mine productivity The UMW's 1974 contract provided a wage-benefit increase of nearly 50 per cent over three years, the highest for a major industry.

According to a Labor Department tabulation, about 2 million workers are covered by major collective bargaining agreements (those involving 1,000 or more workers in the private nonform ecomoy) that expire this year. This contrasts with 4.9 million for last year and 4.4 million for the previous year, the two busiest years of the customary three-year bargaining cycle.

Construction, with 740,000 workers covered by this year's bargaining, along with transportation equipment, maritime and West Coast Longshoring and airlines ground service Trans World Airlines, Eastern, and United).

In addition, the U.S. Postal Service's agreement with unions representing 60,000 postal workers expires in July, with job security - one of the dominant concerns of almost all unions in recent years - heading the list of the isles.

IT is in the area of deferred wage increases and cost of living hikes, however, that the largest amount of activity will take place.

Roughly 6.3 million workers will receive scheduled wage increase averaging 5.1 per cent over the nexty ear, according to Labor Department projections. Of these, 4.1 million are also in line to receive cost-of-living increases because of escalator clauses in their contracts, the department said.

The largest concentration of workers receiving deferred wage increases in in the metalworking industries such as autos, according to the department's report. Other major industries where wage hikes was scheduled are construction (those workers who are not negotiating this year) and telephone.