Yesterday may have been the time to invade Iceland.

The president was on strike.

Vigdis Finnbogadottir joined tens of thousands of female executives, employes and housewives who staged a 24-hour strike to protest male privilege in the home and work place.

Calls to President Finnbogadottir's office in Reykjavik were unproductive. A man identifying himself as "Hans" would only say, "Nobody's here. They went out."

There are 240,000 people -- and 2 million sheep and very few trees -- in Iceland. Nearly 80 percent of the country's women work, and on the average they earn 40 percent less than the men. Women are entitled to equal pay for equal work but few hold top executive jobs.

Hordes of grumpy men crowded into hotel restaurants after their wives refused to cook their breakfasts, wire services reported. Most schools were closed and offices were largely deserted. Supermarkets told their employes to stay home after thousands of female shop assistants failed to go to work. Switchboards went unmanned . . . uh, unstaffed. Many male employers threatened to withhold a day's wages from strikers.

The presidency is more ceremonial than political. "I always find it difficult to describe what I'm doing all day," Finnbogadottir told The Washington Post two years ago. "Anybody in Iceland can make an appointment to see the president."

Finnbogadottir, 55, was running a theater company when, in the traditional Icelandic way, a group asked her to stand for national election. She is the fourth president of the Republic of Iceland, which declared its independence from Denmark 41 years ago.

Kirsten Ockens, who works for Icelandair in New York, said women in her office thought the strike was "really wonderful. But wouldn't it be weird if President Reagan went out on strike? I guess he wouldn't do it."

Prime Minister Steingrimur Hermannsson, the top official in the Icelandic government, is in the United States but could not be reached for comment.

The strike is a near replica of a one-day stoppage called in Iceland 10 years ago when the United Nations decreed an International Women's Decade. The strike slogan is "We dare, we can, we will."

Not all women in Iceland supported the walkout. In the fishing village of Hellissandur, women told a Reuters reporter that they only wanted higher wages for their men so they themselves would be freer to devote themselves to their homes and children.