A boat packed with refugees from Vietnam capsized in rough seas today after Malaysian police barred it from docking, leaving 142 drowned or missing, police said.

Another 148 refugees were rescued, authorities said.

The boat was about 200 yards from shore when it capsized in the South China Sea at Pantai Ru, some 195 miles northeast of Kuala Lumpur.

The boat left Vietnam on Nov. 26 and arrived at Pantai Ru yesterday evening. But police assisted by troops went to the beach and prevented the Vietnamese from landing.

So far 43 bodies have been recovered, and the search is continuing for 99 others missing.

It was the fourth refugee boat to capsize in rough seas in the past 10 days. On Nov. 22, a refugee boat hit a sand bank and capsized in the rough waters of the Trenggann River estuary 180 miles northeast of Kuala Lumpur, leaving 105 dead and 84 missing. Police had turned the craft away, apparently judging it seaworthy.

Malaysia accepted the boat people liberally since the war ended in Vietnam in April 1975. But in November the influx increased to 500 daily, pushing the refugee population in Malaysian camps to over 45,000.

Because of the increased influx, Malaysia mounted naval patrols last week to turn away all seaworthy refugee boats.

The Malaysian government has refused to accept the Vietnamese immigrants, whom it regards as illegal immigrants. One freighter, the Hai Hong, has been anchored off the Malaysian coast since Nov. 9.