Only a small portion of the 29,000 tons of relief supplies that have reached Cambodia have been distributed to Cambodian people, Senior UNICEF and international Red Cross officials said today.

Jean-Pierre Iiocke said new shipments of trucks into Cambodia and new commitments by the Cambodian government should speed distribution. The next several weeks will be a critical test, he added.

Hocke, the International Committee of the Red Cross operations director who recently visited Cambodia, said the enormous logistical problems in that devastated nation had prevented faster distribution although "we would have liked to see things go faster."

He denied news reports that attributed distribution delays to political actions by the Heng Samrin government, which was installed by Vietnam last January after Vietnamese troops toppled the Pol Pot government.

"No more than a few thousand tons have been distributed," Hocke said. UNICEF Eexecutive Director Henry Labouisse told the same news conference that "we are pressing the [Cambodian] government to take action." Both men said, however, that their organizations are not setting any deadline or delivering an ultimatum to Cambodian authorities.

Labouisse said the choice is between continuing to try to help and turning one's back on Cambodia's hungry people.

Hocke said there is no evidence of large-scale, general famine in Cambodia, but that there are serious shortages of food and medicine. He predicted that the period from May or June until the end of next year, when the next regular wet season harvest is complete, will be critical.

The Red Cross and UNICEF, which have jointly undertaken relief efforts in Cambodia, set a target of distribution of 1,000 tons a day.

International relief officials have had 60 trucks in Cambodia, but some have been loaned to government ministries, or made available to the government for special duties, Hocke said.

The two international agencies have just delivered 100 more trucks and expect an additional 155 to be in Cambodia by the end of this month, Labouisse said.

The Soviet Union is sending between 200 and 250 trucks to help with the relief effort, he added.

Hocke said the new trucks, plus agreement from the government to permit more extensive travel by relief officials and additional logistical help from Vietnam, should speed deliveries.

The international relief supplies are piled in warehouses, mostly in the port city of Kompong Som. There are no indications of spoilage because the goods have not been in Cambodia very long, Hocke said.

Labouisse said that by the end of January the international agencies will have spent $31 million more than they have collected so far, and he appealed for additional funds from governments and private sources.

In another development, Leo Cherne, the head of the Citizens Commission on Indochinese Refugees, told a House subcommittee hearing that the Vietnamese government, "with the concurrence and perhaps the encouragement of the Soviet Union, has adopted a conscious policy of withholding adequate relief supplies from the Cambodian people."