President Reagan tried to increase the pressure on Israel yesterday to agree to a timetable for withdrawing its troops from Lebanon, saying "the time is now for action."

Reagan made his comment during an interview with The Washington Post, covering many other subjects, hours after U.S. ambassadors Philip C. Habib and Morris Draper met in Jerusalem with Israeli Prime Minister Menachem Begin.

Administration officials hinted earlier in the day that the president was growing impatient with Israeli demands that all remaining forces of the Palestine Liberation Organization be withdrawn from Lebanon before other troops leave. Without publicly chiding Begin or giving details of the U.S. proposal, the president conveyed this impatience in the language he used to describe the necessity for immediate withdrawal of all foreign forces.

"The government of Lebanon should be sovereign over its own territory, and we think the time has come now for the foreign forces that are in there -- Syria, Israel and the remnant of the PLO that is in there--to get out and that's why the multinational force was sent . . . ," Reagan said. "For those countries to delay in getting out now places them in the position of being occupying armies."

Reagan repeated this point a moment later, saying it was one thing for the Israelis to be in Lebanon when they were invited or when they were being attacked across the border and another to be there now.

"The Lebanese government has enough confidence in itself that it has asked them to leave and to not leave is, as I say, to make themselves occupying forces," Reagan said.

His comments came amidst speculation in Israel that Begin was prepared to back down on his insistence that some of the negotiations on troop withdrawal be held in Jerusalem. Israel has ruled out shuttle diplomacy conducted by Habib and Draper between Lebanon and Israel, and Reagan administration sources said yesterday that the likely compromise is direct Israeli-Lebanon talks in a western European city, probably Rome.

The president did not comment on specific proposals yesterday or on the substantive question of whether the PLO troops should leave Lebanon first, saying that these are "details to be worked out."

But Reagan did reflect the concern shared by high officials in his administration that the stalemate on the troop withdrawals was getting in the way of serious discussions of the Middle East peace initiative the president offered last September.

Once the troop withdrawals from Lebanon are negotiated, Reagan said, "we can get on with the business of the major negotiations to bring about peace and eliminate the differences that have kept the Middle East in turmoil all this time."

Reagan described his September plan as "a complete proposal leading to solution of all the problems in the Middle East, and it begins with recognizing the sovereignty of Lebanon after all these years of division . . . . "

As weeks have passed with little progress, there has been a growing concern in the high councils of the Reagan administration that the president's plan would lose its initial momentum while Israeli and other foreign forces remained in Lebanon indefinitely. Reagan was described by officials as determined to end this impasse and as holding what one official called "a firm view" that foreign forces must be withdrawn, preferably at the same time.

Reagan's appeal for withdrawal was cast in general terms in order not to undercut the negotiations of Habib and Draper. But U.S. officials readily acknowledged that the president had Israel in mind when he talked about the necessity of troop withdrawal.

The president's comments were a kind of public jawboning directed to the same points that Habib and Draper have pressed in their private discussions with Israeli officials. The two diplomats left the United States with instructions to break the procedural deadlock and get the discussions under way.

According to U.S. officials, they were empowered to tell Begin that Israeli willingness to resolve the procedural issues would be viewed as a test of its seriousness about withdrawing from Lebanon.

The Lebanese government repeatedly has pressed the administration to step up its pressure on Israel to remove its troops.