The immigration department has denied claims hundreds of Vietnamese asylum seekers staged a 24-hour hunger strike at a detention centre near Perth.

The denial follows refugee activists' claims on Sunday that asylum seekers at the secure Yongah Hill detention centre had stopped eating because Vietnamese police had been granted access to the centre by officials.

The detainees were also said to be protesting a crackdown by police in the province of Vinh where many of the asylum seekers come from.

The immigration department says the reports were wrong.

"There was absolutely no hunger strike going on at the centre yesterday," a department spokeswoman told AAP on Monday.

"The mood at the centre (was) calm all weekend ... no incidents, no protests, nothing like that."

She said two people at the facility, who weren't Vietnamese, stopped eating on Friday but resumed on Saturday.

"They were the only people who had refused meals," she said.

Reports that hundreds of asylum seekers were on a hunger strike had resulted from "unsubstantiated and irresponsible misinformation" disseminated by the Refugee Action Coalition's Ian Rintoul, she said.

Five Vietnamese men escaped from Yongah Hill on August 17.

Four were caught within four days but a fifth evaded recapture for eight days.