The permanent processing facility for asylum seekers in Papua New Guinea could take up to two years to build, says Manus Island MP Ronnie Knight.
A permanent 600-bed centre was due for completion in January but a 3000 capacity facility is now needed.
"I believe that it will take about two years to build a permanent facility," he told ABC television's 7.30 Report on Monday.
"Their option now would be most realistically to extend the temporary facility.
"That could be done in a couple of days, depending on how many tents and dongas they need."
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Mr Knight doubts Prime Minister Kevin Rudd's claim that approved refugees will eventually be settled in PNG.
"The track to get citizenship in Papua New Guinea is probably more stringent than for (a person) to get Australian citizenship," he said.
"There's certain conditions that I don't think any of those asylum seekers will be able to meet."
Instead, asylum seekers might be transferred to third countries in the region "that maybe owe Papua New Guinea some favours", Mr Knight said.
"You're looking at other Pacific countries, maybe New Zealand," he said.
Immigration Minister Tony Burke says four boats have arrived since Mr Rudd made his PNG announcement on Friday.
The passengers on those boats will eventually be transferred to PNG in around two weeks once health checks are made.
Mr Burke said authorities have started to remove the 215 asylum seekers that were on Manus Island on Friday before the PNG announcement to make way for transfers under the new regime.
The immigration department has confirmed that there are now 130 asylum seekers remaining on the island, suggesting 85 people have been removed.
Mr Knight said Mr Rudd's "brave plan" will make a difference in stopping the boats.
"I know it will put a stop to a lot of people coming to Australia if they know they're going to be stuck in Manus for three or four years," he said.
"Maybe it's just one of those things that will make them think twice before trying to come through the backdoor."
