The first truck convoys of Red Cross and U.N. relief supplies got through today to civilians in war-shaken Tyre, Sidon and the Bekaa Valley of Lebanon, the agencies reported.

So far, however, Israel has not given permission for relief shipments to Beirut, said Iqbal Akhund, a Pakistani appointed as the United Nations' chief humanitarian representative for Lebanon.

Officials here said the U.N. Children's Fund and the International Committee of the Red Cross sent a truck convoy down the Damascus-Beirut highway today to see how far it could get through negotiation with Syrian and Israeli officers commanding local roadblocks. As of tonight, there was no word from U.N. and Red Cross officials in Beirut that the convoy had made it through.

"We have also launched a test by sea, to see if the Israelis stop us," said a Red Cross official here.

A ship with 500 tons of relief supplies has been dispatched from Cyprus, he said, to see whether Israeli naval units blockading the Lebanese coast would allow it to land at either the port of Junieh, in the north, or at the docks in Beirut.

The Israelis let two ships through to Junieh today, the Red Cross reported--French and Italian vessels sent to evacuate French and Italian nationals from Lebanon. In addition, an ICRC field representative made it through to Junieh on a small sailboat today, the Geneva-based group reported.

The Israelis did permit the Red Cross committee to land four planeloads of tents, medicines and food in Tel Aviv yesterday and truck it up the coast to Tyre and Sidon today, Israeli and ICRC officials confirmed. The goods will be distributed by Red Cross representatives and members of the 7,000-man U.N. peace force in Lebanon.

"We had trouble with the Israelis in the beginning," said the Red Cross official, "but now cooperation is getting better, at least on this route."

The group is seeking permission to have its officials check the conditions of Palestinian prisoners taken by Israel. The United Nations and Red Cross both sent two planeloads of goods--blankets, medical supplies, tents, soap, vegetable oil and water purification tablets--to Damascus. The first planeload was dispatched by truck to Lebanese and Palestinian civilians in the Bekaa Valley, which remains under the control of Syrian troops.

The hope is that the rest can reach the more than 600,000 civilians in West Beirut, which is encircled by Israeli troops and their Lebanese Christian allies, and which Israel appears reluctant to supply with humanitarian aid.

The International Committee of the Red Cross now has 57 officials in the field in Lebanon and estimates that 100,000 to 300,000 civilians have been "affected" by the fighting and need aid. The United Nations estimates the number at 600,000, while the Lebanese say that 1.5 million need relief help.

In the Tyre and Sidon areas, occupied by Israeli forces, the ICRC has brought in Finnish and Norwegian medical teams to help the local hospitals.