More than 150,000 refugees fleeing a guerrilla war and drought in Mozambique are likely to arrive in neighboring Malawi over the next nine months, adding enormous strains to an already-taxed relief effort, the State Department said Tuesday. Malawi currently provides haven for 450,000 Mozambican refugees, but ``the population in Malawi is rapidly increasing and the most conservative estimates forecast 600,000 refugees will arrive by December 1988,'' according to a State Department report. The report said other African countries also are receiving large numbers of refugees. There are 75,000 in Zimbabwe, 30,000 in Zambia, 225,000 in South Africa, 72,000 in Tanzania and 20,000 in Swaziland. Within Mozambique, there are 1.6 million displaced people, the department said. ``Complicating the refugee situation is that Malawi has also experienced a drought and a mealy bug infestation,'' the department said. ``More than one million Malawians no longer have the resources to feed themselves.'' A consultant hired by the State Department to assess the magnitude of the problem and recommend U.S. responses said he interviewed a selected, geographically diverse sample of 200 refugees in camps between January and March. The consultant, at a background briefing arranged by the Bureau of Refugee Programs, said 91 percent of those he interviewed reported they Mozambique because of fighting between RENAMO, a potent guerrilla movement, and the Maputo government. The war has been going on since the mid-1970s. ``It reflects an intensity in the level of violence over the period of the last year,'' the expert said. ``I think the drought is an aggravating factor in increasing the refugee flows, but according to the refugees with whom I spoke, the great majority fled because of RENAMO related violence.'' The State Department has pledged $4.4 million to a UN special appeal for Mozambican refugees in Malawi. This is in addition to $33.4 million contributed to the UN's program covering all of Africa.