In a move that will be closely watched by the Carter administration, Britain's Labor government called yesterday for a fourth consecutive year of specific curbs on pay demands.

Denis Healey, the Chancellor of the Exchequer, announced that the goal for the next 12 months is wage increases averaging 5 percent - just half the target of the past year.

With a possible general election in October and almost certainly no later than next spring, the likelihood of pay deals not far above the target is good. Unions here are the backbone of the Labor Party. Their leaders will not want to wreck the government's electoral hopes.

As in the past three years, the pay program is largely voluntary. It depends essentially on the assent of union leaders and their members.

Up to now, this incomes policy has been the Labor government's most conspicuous sucess. It has played a major part in bringing inflation down from 30 percent to the current rate of 7.4 percent.

Three years ago, prices here were spiraling upward so rapidly that some commentators feared Britain's stable democracy was in danger. Now, with inflation at the average European level, such talk has died away.

This achievement has been closely monitored by top economic officials in the Carter administration. On visits here, several U.S. spokesmen have said in private they believe American must adopt some similar form of incomes policy.

Nearly all the more successful economies in Europe - notably the German, Swedish and Dutch - have turned to incomes policies. But traditional belief and powerful institutional resistance from both corporations and unions have made the subject almost taboo in the U.S.

In Britain, the Labor government punishes private companies that breach the pay target, stripping them of government contracts, subsidies and export credits. Although the targets are exceeded, the deals have been close enough to the goal to bring inflation down. This past year, for example, earnings have been increasing by 14 percent compared to a 10 percent target.

Prince increases are not as great for two reasons. Workers have become more productive each year here. Moreover, the flood of oil from the North Sea has strengthened the pound and made imports of raw materials cheaper.

Perhaps the most remarkable feature of the British experience has been the fact that until this year, workers were accepting wage increases less than price rises; real incomes have been falling. The discontent generated by this fall in incomes is perhaps the strongest point that opposition Conservatives can emphasize in the election campaign.

The Labor government plans to make incomes policy a permanent feature on Britain's economic landscape. To make the pay curb more palatable, Healey will ask Parliament to continue for another year the law that limits divident increase to 10 percent, although in a somewhat more relaxed form.

Since Labor no longer commands a majority in the Commons, the government may very well lose the bill, but Prime Minister James Callaghan won't mind that too much. He can use it as an election argument, charging history opponents with class bias.