MANAGUA, Nicar (AP) _ About 60,000 government workers staged sit-in strikes Friday, demanding 200 percent pay increases and paralyzing the new administration as it struggles to rebuild Nicaragua's shattered economy.

In a showdown with the Sandinista-dominated civil service, President Violeta Barrios de Chamorro's government threatened to declare the strike illegal and fire those who do not return to work.

The strikers also are demanding the restoration of a repealed civil service law that protected public employees from firing and gave fringe benefits that Mrs. Chamorro said her government cannot afford.

''We have inherited a country that was virtually sacked and in complete bankruptcy and it is our responsibility to get it going again,'' she told a news conference.

Mrs. Chamorro, inaugurated April 25, announced her government would review all laws passed by the leftist Sandinistas their last two months in office.

At the time, the Sandinistas had control of the National Assembly, but Mrs. Chamorro's 14-party United National Opposition took a majority in the parliament with its victory in elections Feb. 25.

Public employees - a majority of them Sandinistas - occupied almost all ministry buildings Thursday night and early Friday, virtually paralyzing her government.

The 300 employees at the presidential office building where she talked to reporters sat around idle.

Labor Minister Francisco Rosales told the news conference: ''Workers on strike should return to their jobs, otherwise we will declare the strike illegal and apply the Labor Law and those who do not show up will be fired.''

Mrs. Chamorro said her government would revise ''all the laws and decrees enacted by the previous government from Feb. 25 to April 25, since what constitutes the nation's capital cannot be appropriated in an arbitrary manner.''

Mrs. Chamorro said some of the earlier laws passed by the Sandinistas will also be revised, including some that confiscated private businesses and turned them into state enterprises.

They include laws forcing big landowners to rent their land to state-run cooperatives. She said a return to privately run farming was needed to revive farm production for the next planting season, which begins in about two months.

Food production dropped so sharply under the Sandinistas - and during the U.S.-imposed economic embargo - that Nicaragua was forced to import crops it used to export and shortages occurred of such staples as rice and beans. The Bush administration lifted the embargo on the day the U.S.-backed candidate was inaugurated.

Another law being revised allowed senior Sandinistas to confiscate homes of the wealthy.

Rosales said the government will negotiate wage increases ''but it will not do this under pressure.'' He said the civil service law, which organized public employees, was unconstitutional.

He talked to reporters as he struggled with his keys to open the door of the Labor Ministry, which the strikers had locked shut.

Government employees rejected a 60 percent pay increase Mrs. Chamorro had ordered this week when she announced a 9 percent devaluation of the cordoba, Nicaragua's currency. The cordoba has been devalued four times in less than a month.

The devaluations make imports more expensive and encourage exports by making them cheaper. The moves have sent consumer prices soaring.

A subsidy for public transportation was withdrawn, water rates were doubled, electricity rates tripled and telephone service increased 1,300 percent.

The cordoba traded at 180,000 to the dollar on the parallel market, an official rate for most currency transactions. The rate when the Sandinistas took over in 1979 was 10 per dollar, and 38,150 to the dollar in January.

''Prices of clothes have shot up barbarously,'' said Clarissa Gutierrez, 50, a janitor at the education ministry.

She makes 4.8 million cordobas a month - $26.66 at the parallel rate. ''This doesn't even feed me for 15 days.,''

Mrs. Gutierrez complained that a pound of sugar now costs 50 cents, rice 40 cents, beans 55 cents, and a quart of cooking oil $3.

But Roberto Martinez, 40, who has a stall at Managua's sprawling Eastern Market, hoped for better times. ''Things will change. The new government is just getting started. We suffered more under the Sandinistas.

''The Sandinistas had us down on the canvas. The new government says they stole everything,'' Martinez added.