MANILA, Philippines (AP) _ A tanker and passenger ship apparently had no time to radio for help after colliding and vanished in a huge fireball just minutes after the few survivors were plucked from the sea, the captain of the first vessel to reach the scene said today.

Capt. Melecio Barranco of the ferry Don Claudio said the flames were so huge he could not make out, even with binoculars, either the 2,215-ton Dona Paz or the oil-laden 629-ton Victor.

The two ships exploded in flames and sank Dec. 20 in the Tablas Straits off Mindoro island 110 miles southeast of Manila in the century's worst peacetime disaster at sea.

An estimated 1,630 people were listed as missing and presumed dead in the disaster, but no one knows exactly how many people were aboard the Dona Paz.

Barranco spoke to the Philippine Coast Guard's Board of Marine Inquiry as it began a formal inquiry into the collision.

The Don Claudio was steaming toward Manila at 10:30 p.m. when a lookout spotted fire and thick smoke eight miles away, Barranco told the board. He said he was on the scene about 45 minutes later, rescuing survivors.

Barranco said the stricken vessels appeared on his radar screen only as one mass, and he could not not see either of them because of the fire, which he described as being ''as big as a 10-story building.''

''At 12:10 a.m., a big ball of flame shot up into the sky,'' Barranco said. ''When the flames subsided, the object on the radar screen was gone.''

By then all of the 26 known survivors had been rescued: 24 Don Paz passengers and two of the tanker's 13 crew members.

Barranco said his ship and at least four other vessels that apparently responded to radio messages from the Don Claudio searched the area for two more hours but found nothing.

''All we saw were pieces of styrofoam,'' he added.

The captain said none of the 26 survivors had life jackets. The coast guard said only 133 bodies had been recovered.

Earlier, Vicente Gambito, vice president of the Sulpicio Lines Inc., owner of the Dona Paz, said he did not think the Dona Paz was able to send out any distress messages. Barranco said his radio operator had not picked up a distress signal from either ship.

On questioning from board members, Barranco said two tanker crewmen told him they were asleep when the collision occurred.

''They said that when they woke up, their ship was already on fire and they immediately jumped into the water,'' he said.

Coast guard officials said they have failed to locate either of the crewmen, who Barranco said suffered only minors burns.

Sulpicio Lines officials said earlier that 1,583 passengers and 60 crewmen were listed on the Dona Paz' manifest. Philippine passenger manifests do not include children and people who buy tickets aboard ship.

On questioning by board members and lawyers representing the victims, Gambito said the Dona Paz had at least 1,562 passengers, 44 more than its authorized capacity of 1,518.

Capt. Dario Fajardo, chairman of the five-member board and deputy coast guard commander, said he will subpoena officials of Victor Shipping Corp., the reported owner of the tanker. The company has refused to make any statement since the disaster.