The House Foreign Affairs Committee yesterday voted, 18-to-5, to increase military grants to Israel $300 million more than President Reagan requested in his 1984 budget.

Hopping agilely through a political and diplomatic mine field, Deputy Secretary of State Alvin P. Drischler told the committee, "We support the administration's request. But we do not oppose the add-on."

The packed committee room erupted into laughter as Chairman Clement J. Zablocki (D-Wis.) complained, "We're confused."

The House action, which follows approval of increased aid to Israel by the Senate Foreign Relations Committee last week, comes at a delicate time in negotiations over the withdrawal of Israeli and Syrian troops from Lebanon.

Rep. Joel Pritchard (D-Ind.), who sponsored an unsuccessful amendment to keep aid to Israel at $550 million in military grants and $1.15 billion in military loans, as the administration had proposed, argued that Secretary of State George P. Shultz would lose flexibility in the negotiations if Congress unilaterally increases the grants.

"There's always been the feeling that in Congress, Israel has enough support to checkmate any administrative initiative," Pritchard said. "The administration can't call the tune of American policy."

Rep. George W. Crockett Jr. (D-Mich.), reflecting congressional uneasiness over Israeli policy on the West Bank, said the increase in grants "frees additional capital for Prime Minister Menachem Begin to continue building settlements in the occupied territory."

However, opponents of the Pritchard amendment said $850 million in grants is essential because of Soviet aid to Syria. Rep. Stephen J. Solarz (D-N.Y.) said that to give Israel less would be seen "as a failure to recognize the significance of their concessions" in negotiations over troop withdrawals.

Rep. Larry Winn Jr. (R-Kan.) argued that the increase would "help Israel to meet its debt service to the U.S., which amounted to over a billion dollars in 1983."

In all, Israel would receive $1.7 billion in military loans and grants and $850 million in economic aid under the House bill. That is more than any other nation receives.

The committee also voted for an amendment sponsored by Rep. Gus Yatron (D-Pa.) to embargo military aid to Greece or Turkey at the end of fiscal 1986 if they have more troops on Cyprus than allowed by a 1959 treaty.

"This amendment allows Turkey three more years to withdraw its troops from Cyprus, which would be a total of 12 years since it first invaded this small island nation," Yatron said. "If we are going to authorize almost a billion dollars in military and economic assistance to Turkey, I don't think it is asking too much for Turkey to withdraw its troops from Cyprus."

Opponents of the amendment, including the administration, argued that it would sour relations with Turkey, a key NATO ally. The previous aid embargo against Turkey was unsuccessful in achieving a troop withdrawal, they said.

The Senate Foreign Relations Committee, meanwhile, narrowly defeated an administration-backed plan to add $237 million to the aid levels tentatively approved by the committee for several countries.