Chinese crew detained after WA arrival

Eight Chinese crew members found on a boat intercepted off the West Australian coast have been taken into immigration detention.

The boat was found near Geraldton on WA's Mid West coast on Sunday and was searched by firefighters wearing protective suits, who removed items contained in secure bins on Tuesday.

Geraldton local Brody Boyle, who was working on the foreshore when the boat arrived at the port, said he saw WA Police and Border Force officers swoop on the jetty.

He said up to five people who had been on the boat were made to sit down for about an hour then were whisked away in vans.

"They weren't on the jetty for too long," Mr Boyle told AAP on Wednesday.

An Australian Federal Police spokeswoman said none of the eight Chinese nationals had been charged and were taken into custody because they did not have valid visas.

The AFP deemed the boat "suspicious" but confirmed no asylum seekers were aboard.

Mr Boyle said there was a lot of speculation around town that high-powered boats were found under the deck of the main vessel and could have been used to bring illegal drugs to shore.