Poland's suspended Solidarity trade union, in a bold action yesterday during ceremonies commemorating the Warsaw uprising during World War II, played a taped speech from an underground leader calling for continued resistance to martial law.

Thousands of chanting Poles flashed victory signs and demanded the release of Solidarity leader Lech Walesa as military bands played patriotic music at the ceremonies in a cemetary in western Poland.

Sound equipment mounted secretly on a monument to veterans of the Home Army, which launched the Warsaw revolt against Nazi occupiers on Aug. 1, 1944, broadcast a recorded appeal by fugitive Solidarity leader Zbigniew Bujak.

"We shall fight for the rights of Solidarity," Bujak declared. "We shall fight for the revival of independent unions. We shall fight for the release of our colleagues." The message was repeated three times.

Last week, Bujak and other fugitive union leaders called for a wave of protests and demonstrations to culminate on Aug. 31, the second anniversary of the Gdansk agreement, which paved the way for the formation of Solidarity. The union activists also rejected recent relaxations of martial law by the Polish military government.

The annual ceremonies mark the 63-day Warsaw uprising in 1943 by the underground Home Army loyal to the Polish government-in-exile in London and the smaller Communist People's Army. About 15,000 soldiers and 180,000 civilians died during the uprising.