NEW YORK (AP) _ Uri Lubrani, Israel's chief hostage negotiator, suggested that kidnap groups may have withheld information about missing soldier Yossi Fink to raise the price of a deal.

But he warned Israel would not pay a higher price for information it was promised on the fate of British-born Fink and four other soldiers missing in Lebanon.

''We have no intention of moving until the commitments promised to us have been fully complied with,'' Lubrani told The Associated Press on Friday. ''I can tell you right now we are not budging.''

Lubrani rejected claims by pro-Iranian groups in Lebanon that contended Israel reneged on an agreement to release 20 Arab prisoners. One of the groups canceled the release of an American hostage.

Lubrani, head of Lebanon policy for Israel's ministry of defense, said Israel released 51 Arab detainees and the bodies of nine guerrillas last month even though the kidnap groups did not make good on promises to account for missing Israelis.

Forensic information given to Israel through United Nations negotiators last month established that Israeli soldier Rehamim Alsheikh was dead, and the body of another soldier, Samir Assad, was flown back to Israel.

But Lubrani said Israel received inadequate information about Fink, who was captured in south Lebanon by Shiite Muslim guerrillas in February 1986 along with Alsheikh.

Abbas Musawi, leader of the Hezbollah in Beirut, told reporters when asked about Fink earlier this week that ''there is a price for every piece of information.'' He also said Syrian and Palestinians held by Israel should be added to the deal.

Lubrani said Israel was giving a ''clear no'' on further releases of Arabs until it receives proof of Fink's condition is received.

Hezbollah is an umbrellla organization for groups believed to be holding nine Westerners in Lebanon - five Americans, a Briton, two Germans and an Italian. The longest-held is Terry Anderson, the Associated Press chief Middle East correspondent, who was kidnapped March 16, 1985.

A 10th hostage, Briton Alec Collett, is believed to have been killed by his captors.

Of the missing Israelis, only aviator Ron Arad is believed to be alive.

In response to the information on Alsheikh and Assad's body, Israel made a prisoner release while U.N. Secretary General Javier Perez de Cuellar was in Tehran.

The pro-Israeli militia in south Lebanon is holding from 250 to 300 prisoners in a jail at al-Khiam. More than 40 others are held in Israel, including Sheik Abdel-Karim Obeid, a Shiite Muslim clergyman and Hezbollah figure who was abducted by Israeli commandos from his home in south Lebanon.