New pictures have emerged of the asylum seeker boat that was discovered off Western Australia's North West coast earlier this week.

The boat was first spotted by crew members on an oil tanker on Monday morning, about 150 kilometres from Dampier.

The pictures, obtained by the ABC, show people inside the vessel.

Water police were called in to help locate the boat, followed by a Navy ship.

The boat was not brought in to dock at Dampier port and the Federal Government has refused to provide any details, citing operational reasons.

A Vietnamese advocacy group said earlier this week that it was worried the Government would unfairly dismiss the refugee claims of the asylum seekers.

VOICE said it believed up to 30 of the people on the boat were fisherman caught up in a territorial dispute between Vietnam and China.