Two House appropriations subcommittees voted unanimously yesterday to provide $880 million in emergency food aid to African famine victims, more than triple the amount requested by the Reagan administration.

The full Appropriations Committee is expected to approve the emergency measure today. Committee Chairman Jamie L. Whitten (D-Miss.) said he hopes to bring the matter to the House floor for a vote early next week. The Senate is set to begin work on similar measure.

"Where is the money going to come from in view of the deficit?" asked Rep. John Edward Porter (R-Ill.), who nevertheless supported the measure in the House foreign operations subcommittee.

"It's obvious where it's going to come from," responded subcommittee Chairman David R. Obey (D-Wis.). "It's going to be borrowed . . . . This is a life-threatening situation. We have no other course."

The administration requested a $235 million emergency supplemental appropriation for the drought-stricken countries of Africa. Of that amount, $185 million was for food aid and the rest for disaster and refugee assistance.

But, concerned that the White House's emergency request was too small, the subcommittees approved $480 in immediate food aid and $225 million to be held in reserve for up to two years and used at President Reagan's discretion.

Another $175 million would be for non-food disaster and refugee assistance.

The emergency food aid has strong bipartisan support, despite its high price tag.

In testimony before both subcommittees this week, M. Peter McPherson, administrator of the Agency for International Development (AID), said that 29 African nations have been seriously affected by the drought. Ethiopia and Sudan are among the hardest hit.

As a result, hundreds of thousands of Africans have starved to death and millions more are in imminent danger of starvation.

Africa has been plagued by low rainfall since the last 1960s. And as its population increased, its food production has dropped.

The United States has provided steadily increasing amounts of emergency food assistance to African nations, in addition to regular food and grant programs designed to bring about the "greening" of the continent.

According to figures provided by the House Foreign Affairs Africa subcommittee, the United States provided about $173 million in emergency food aid in fiscal 1984. Between Oct. 1, when the current fiscal year began, and the end of January about $348 million was spent.

Some lawmakers have said the administration should have moved more quickly and with greater generosity. They point out that last year Congress provided a much larger emergency aid package than the administration requested.

Some Congress members have suggested that the administration may have been slow to respond to the Ethiopian crisis because that country's government is Marxist, a charge the administration denies.

While there is general agreement that the United States should provide about half of the African food assistance, congressional critics have charged that the administration consistently has underestimated food needs by making overly optimistic appraisals of food supplies in Africa.

"It's hard to nail down exactly what the need is," McPherson told the Appropriations agriculture subcommittee this week. In some areas, he said, "we don't even know how many people there are [much less] how many are starving."