Prime Minister Scott Morrison has parachuted his newest senator into a prime parliamentary role that will have oversight of the hotly contested medevac laws.

Key points: Sarah Henderson became a Liberal senator in September having lost her Lower House seat in May

Sarah Henderson became a Liberal senator in September having lost her Lower House seat in May The Prime Minister has appointed her to take over the Parliamentary Joint Committee on Human Rights

The Prime Minister has appointed her to take over the Parliamentary Joint Committee on Human Rights She replaces WA Liberal MP Ian Goodenough, with the PM keen for a less critical tone on medevac laws

Sarah Henderson, a former frontbencher who lost the seat of Corangamite in the May election, has been quietly appointed chair of the Parliamentary Joint Committee on Human Rights.

Earlier this year, the Liberal moderate was critical of the medevac laws, saying they were not needed and the "political consequence" would be the unravelling of the Coalition's tough border-protection regime.

There is concern among MPs the Prime Minister would like the human rights committee to strike a less critical tone on the medevac laws.

The committee has a strong history of issuing bipartisan reports when it scrutinises legislation.

Last month, the committee expressed concerns about the Government's medevac repeal bill, including the adequacy of access to health care and the right to health for those held under regional processing arrangements and the extent to which the repeal of the medical transfer provisions would, "restrict access to health care for those held on Nauru and Manus Island".

Other MPs and senators on the committee were only informed of Senator Henderson's appointment this morning.

She replaces as chairman fellow Liberal Ian Goodenough, who has been instead encouraged by senior colleagues to consider a vacancy on the procedures committee, which is not known for controversy.

Mr Goodenough's health has been cited as a reason for shifting him from the committee. He has long suffered a kidney complaint.

Sarah Henderson replaces WA Liberal Ian Goodenough as the committee's chair. ( ABC News: Ross Nerdal )

The deputy chair of the committee, Labor's Graham Perrett, said the history of the human rights committee was bipartisan and often critical of government of both stripes.

"The committee's job is to view legislation though the prism of human rights and it's illegal to ignore treaties that we are signatory to," Mr Perrett told the ABC.

"The role of the chair is pivotal. If the chair wants to curry favour with the executive, they might be tempted to hold back on their comments but I think the committee works best when it provides frank and fearless advice on the human rights of Australians and people under our care.

"When [former committee chair and Labor MP] Harry Jenkins was critical of Labor's reopening of Manus, it was with the authority of a former speaker and an experienced member of Parliament.

"It is not a committee that is in bed with the executive and that is the history of the human rights committee and I hope that tradition continues."

Senator Henderson's political career was resurrected last month when she replaced Mitch Fifield.

In February, she was a panellist on Q&A and was critical of Labor's support for the medevac laws.

"Let's not forget who put those people on Nauru and Manus — it was the Labor Party," she said.

"There is no need for this bill. This is all about politics … the political consequences are that Australians will see that Labor will do anything to unravel border protection."

A chair of a joint parliamentary committee receives an 11 per cent allowance, on top of the backbencher's $211,250 base salary, or $23,237 extra.