Anti-Khomeini commandos who hijacked a French-made Iranian missile boat in the Atlantic were reported early today to have allowed French officials to tow the craft from Marseilles to the Mediterranean port of Toulon, 30 miles to the east.

The hijackers sailed into French waters yesterday in an effort to pick up food and fuel, but earlier had been turned away by French authorities who ordered them to head back out to sea. There was no official comment from the government about the towing operation.

French officials in Paris, quoted by news agencies, said the Iranian commandos threatened to blow themselves up along with the captured 147-foot guided missile patrol boat unless they were resupplied. But their threat apparently was not taken seriously.

News agencies quoted informed sources as saying that during negotiations yesterday, French officials urged the approximately 20 well-armed hijackers to leave the boat and go ashore, but the Iranians said they would do so only if a French government representative went aboard. The French reportedly declined to send anyone.

The hijackers seized the missile boat off Cadiz Thursday as it was being delivered to Iran along with two other similar craft turned over to Iranian sailors Aug. 1 at French shipyards in Cherbourg. They used a commandeered Spanish tug to carry out the hijacking.

Despite their difficulties with French officials, the rightist Iranian dissidents -- who were flying the late shah's imperial flag -- have gone a long way toward publicizing their struggle against the radical Islamic government in Tehran led by Ayatollah Ruhollah Khomeini. Although in statements to the press they proclaimed the seized missile boat the seat of a "national government of Iran," their chief goal from the beginning appeared to be attracting attention through a spectacular gesture.

"Vive l'Iran! Vive le shah!" a bearded hijacker carrying a snub-nosed submachine gun shouted at a French television reporter who approached the captured craft in a launch off Marseilles, camera rolling. "Long live Iran! Long live the shah!"

Most antigovernment agitation in Iran and abroad has been the work of leftist groups, particularly the Mujaheddin-e-Khalq guerrillas who support the exiled former president, Abol Hassan Bani-Sadr. The Paris-based group that claimed seizing the missile boat, Azadegan, or "Free People," sympathizes with the overthrown monarchy. Former Iranian prime minister Shahpour Bakhtiar has been reported in contact with the eldest son of the late shah Mohammad Reza Pahlavi, who from his exile in Cairo has proclaimed himself his father's successor. The youth also declared his support yesterday for the hijacking.

The 30-knot patrol boat, the Tabarzin, had pulled to within about a mile of Marseilles before being intercepted by a French frigate, United Press International reported from Paris. Its commando crew demanded to enter the southern French port to resupply and let off about 30 Iranian sailors from the original delivery crew who wanted to end their part in the adventure, the UPI dispatch said.

French Defense Minister Charles Hernu said on French television that the captain and the first mate from the original crew elected to remain aboard.

French pleasure craft -- numerous off southern France in prime August vacation time -- bobbed around the missile boat as Iranian sailors climbed down a ladder into inflatable dinghies and moved to the nearby French Navy vessels, according to Agence France-Presse. A joint communique from the Defense and Foreign ministries in Paris said all those who wanted to leave were taken aboard French ships but that the captured missile boat was ordered back into international waters.

When the commandos issued their reported threat to blow up the boat and themselves along with it, the French warships began maneuvering around the patrol boat to herd it out of French territorial waters without violence, according to French officials quoted by UPI. Hernu said, however, that the warships would not force the commandos to leave and that he was instead counting on their "wisdom" to obey his orders.