Wage increases negotiated in major labor contracts declined slightly last year for the second year in a row, the Labor Department reported yesterday.

In a separate report issued Thursday, the department also said that workdays lost because of strikes declined in 1977 after rising in 1976.

The government's inflation fighters took little solace from the moderation of wage patterns. "It indicates no abtement of (labor cost) pressures on inflation, but no acceleration either," abatement of [labor cost] pressures on Wage and Price Stability.

According to the labor Department report, wage scale increases negotiated last year averaged 7.9 percent for the first year, compared with 8.4 percent in 1976. Increases over the life of the contract amounted to 5.8 percent last year, compared with 6.4 percent in 1976. The figures for 1975 were 10.2 percent for the life of the contract.

When cost-of-living and deffered increases are included, wage increases last year amounted to 7. 8 percent, down from 8.1 percent in 1976 and 8.7 percent in 1975.

Average hourly earnings for manufacturing and other production workers increased by 8 percent up from 7.1 percent the previous year. But total compensation per hour for all workers, including fringe benefits such as health care, rose by 8.6 percent, down from 9 percent in 1976.

Inflation is hovering around 6 to 6.5 percent, and the administration's new inflation plan is designed to bring it down at a rate of a half-a-percentage that 5,600 strikes and lockouts began 1977, the Labor Department reported point a year.

In its report on work stoppages in last year, compared with 5,648 in 1976. Lost working time amounted to 1.7 days per thousand, compared with 1.9 in 1976. An estimated 2.3 million workers were involved in strikes last year, 120,000 fewer than in 1976.

Labor strife in the coal fields accounted for by far the largest share of workdays lost to strikes. Of work stoppages involving 10,000 workers or more, the United Mine Workers accounted for 4.7 million of 9.5 million lost days of production. This included the summer-long wave of wildcat strikes and the union's current national coal strike that began Dec. 6.