The Clinton Administration has chosen to ignore weapons shipments from Iran to the Muslim-led Bosnian Government that in the last year have added considerably to Bosnia's military firepower, American officials said today.

They said the United States has ample evidence of the Iranian deliveries, which are in violation of the United Nations embargo that bans arms shipments to all combatants in the Bosnian civil war. But they said the Administration had not tried in any way to cut off the flow. The Administration said last fall that it would no longer take part in efforts to enforce the embargo on shipments to the Bosnians.

A senior Administration official insisted today that the White House neither approved nor endorsed the Iranians' actions. But after months in which President Clinton and his aides have been unable to persuade American allies to allow arms to flow legally to the Bosnian Muslims, one adviser to Mr. Clinton called Teheran's motivations in making the shipments "understandable."

The new flow of arms and ammunition has not yet put Bosnian Muslim forces on the same plane as their better-armed Bosnian Serb rivals, Administration officials said. But with the shipments of small arms, ammunition and anti-tank weapons amounting to perhaps hundreds of tons, they said it had made the Bosnian Government a more formidable force as a four-month-old cease-fire is about to expire.