CANBERRA, April 27 (Xinhua) -- More than 800 asylum seekers detained in Papua New Guinea (PNG) will not be brought to Australia despite a PNG court decision which ruled their detainment illegal, Australia said on Wednesday.

The 850 men are being detained on Papua New Guinea's Manus Island on behalf of the Australian government, but a PNG Supreme Court ruling overnight determined the detention of asylum seekers on the island was unconstitutional and therefore illegal.

But Australia's Immigration Minister Peter Dutton was "absolutely adamant" that the men would not be brought to Australia despite the ruling.

The minister said once the PNG government has sought advice on how to proceed, Australia would assist the asylum seekers in resettling elsewhere.

"We'll work with PNG and provide what support is needed to help people return to their country of origin or a third country otherwise, but we've been very clear and I repeat it again that these people will not be coming to Australia," Dutton told the Australian Broadcasting Corporation (ABC) on Wednesday.

Dutton said Australia would not be accepting the men as it would encourage people smugglers to recommence bringing people to Australia's shores.

The government's controversial asylum seeker policy is based around deterring people from illegally coming to Australia by refusing entry of any form including in processing and detention centers.

"We'll work with (PNG) because we are as determined as ever to make sure these boats don't restart. I'm not going to allow boats to recommence," Dutton sad.

"I do want to see people exit Manus Island and Nauru but we will help them go back to their country of origin or to a third country and settle there, but we are absolutely adamant that people won't be permanently settling in this country."

In the wake of the ruling, both the Opposition and the Greens parties have slammed the government's policy as inhumane, and demanded the men be brought to Australia.