The Australian Greens' new immigration spokesman, Tasmanian senator Nick McKim, will today move to arrange a trip to both Nauru and Manus Islands.

Key points: McKim says he "will give everything I've got" to close camps on Manus and Nauru

McKim says he "will give everything I've got" to close camps on Manus and Nauru Analyst says immigration a "significant issue for the Greens", McKim rewarded for experience

Analyst says immigration a "significant issue for the Greens", McKim rewarded for experience Decision to dump Sarah Hanson-Young took many by surprise

Senator McKim was announced as the Greens immigration spokesman yesterday, taking over from South Australian senator Sarah Hanson-Young.

Speaking exclusively to the ABC, Senator McKim said he would today start the process to travel to both Nauru and Manus Island.

"I'll be moving to institute visa requests and appropriate requests to the relevant authorities to see whether I can visit both Manus and Nauru," he said.

"I've always believed in politics that the best way to inform yourself about issues is to see them for yourself.

"I will give everything I've got to close the camps on Manus and Nauru and bring the people who are currently on Manus and Nauru back to Australia."

The decision to dump Senator Hanson-Young took many by surprise but she will be kept busy with the Education, Finance, Trade, Water, Arts and Youth portfolios.

Senator McKim gave his predecessor a glowing endorsement, and said there was no plans to change any of the Greens' immigration policies — but he said there would be some differences.

"The simple fact is I am not Sarah and Sarah is not me, and inevitably we will have different ways of expressing ourselves," he said.

"But that shouldn't be taken to be any indication at all that we are downgrading our work in this area or that our policy will change."

Senator Hanson-Young has expressed her disappointment with losing immigration and said she fought hard to keep it.

Greens leader Richard Di Natale said she "had done an incredible job".

"She's led the charge on a more humane, compassionate and decent approach to the treatment of refugees," he said.

"[But] after nine years, it's time I think to refresh and reinvigorate the team."

Immigration a 'very significant issue for the Greens', analyst says

Senator Hanson-Young's time at the helm was eventful.

She alleges that during a previous visit in 2013 she was subject to covert surveillance from security guards on Nauru who gave her the code-name "Raven".

Just this week her application to return to the island was rejected.

The University of Tasmania's political analyst Richard Eccelston said Senator McKim had big shoes to fill.

"Immigration is a particularly important portfolio for the Greens because they've been alone really in their opposition to offshore processing of asylum seekers," he said.

"It is a very significant issue for the Greens and for the left in Australian politcs."

Just one month ago Senator McKim was battling for his political survival.

He secured the last Senate spot in Tasmania by just 141 votes, from a One Nation candidate.

Senator McKim is a former Tasmanian Greens leader and state government minister in Tasmania's previous minority government.

Mr Eccleston said he was being rewarded for his experience.

"The allocation of the portfolio to McKim, I guess, recognises his considerable experience in state politics," he said.

"He's one of the few Greens that can say they've had ministerial experience."