TOKYO (AFP) - Japan's coastguard on Monday conducted the second day of a search for seven Japanese and Indonesian crew missing after a tuna fishing boat caught fire in the Pacific at the weekend.

The Japanese-registered No. 8 Kaisei-maru, with two Japanese and five Indonesian men on board, was destroyed in the fire on Sunday some 410km south of Kochi prefecture in western Japan, the coastguard said in a statement.

Two patrol ships and one airplane were scouring the area, but "we have not found any clue to the fate of the crew," an official said "The ship is now also missing after we last spotted it Sunday afternoon," the official said.

"It may have gone down."

The coastguard received a report from a local fisheries radio station early on Sunday that it could not contact the 19-tonne vessel.

More than four hours later, a plane spotted the burning ship, with footage showing the bridge was in flames. It was unclear what caused the blaze.

The ship left the port of Kochi on Feb 20 and had planned to reach another port in nearby Wakayama prefecture on Tuesday.