Around 300 protesters - mostly from the Greens, the Socialist Alliance and the Refugee Action Collective - marched around Brisbane's CBD on Sunday afternoon vowing bigger protests this week.

Singing out "Pack Up Kevin and Throw Away the Key" they objected angrily, but peacefully, to sending refugees arriving by boat to Papua New Guinea.

One sign symbolises the protesters' story; "Seeking Asylum is Not a Crime."

Queensland Refugee Action Collective spokesman Tim Arnot, who lead the calls from the protesters, said people would protest against Prime Minister Kevin Rudd's policy.

"This rally was called in an emergency response to the statement from Kevin Rudd," he said.

"But there is a series of protests taking place - one at 9am outside Kevin Rudd's office on Monday morning.

"And one on Saturday at 1pm, here again King George Square."

The Refugee Action Collective believes detaining refugee is a "blatant rejection" of the rights that refugees should expect.

"That includes the refugee convention that Australia has signed says that anybody who comes seeking asylum to this country, they are entitled to have their claim processed here and also - if they choose - to be resettled here," he said.

"[Rudd's policy] is a flagrant rejection of that."

Mr Arnot said many young people were beginning to question why Australian wants to push its refugee problems to a third country.

"Refugees have already faced trauma enough, to send them somewhere else where they may not have the intention of being re-settled, well that is just a blatant disregard of human rights," he said.

The protests have been organised through social media.