A formal complaint has been made by Plaid Cymru over a top health job for a former Labour minister.
Win Griffiths says an independent assessor helped appoint him
Win Griffiths, who stood down as Bridgend MP at the election, has become chairman of Bro Morgannwg NHS Trust.
Plaid's Rhodri Glyn Thomas, who will protest to the Welsh Administration Ombudsman, said it "smacks of the worst type of Labour cronyism".
But Mr Griffiths said that with his experience he was happy for any scrutiny of his appointment.
Mr Griffiths, aged 62, was an MP for 18 years, including a stint as Welsh health minister in the late 1990s. Previously he had been a Euro-MP for eight years.
He took up his new role on Wednesday at Bro Morgannwg, which covers the Bridgend, Neath-Port Talbot and western Vale of Glamorgan areas.
But Mr Thomas, Plaid's health spokesman, said he would refer it to the newly-appointed ombudsman, who deals with complaints about public bodies.
"I am sure that Win Griffiths is well qualified, but there should be a proper period of separation between a political career and being appointed to this kind of post," said Mr Thomas.
"This position should not be subject to political patronage.
"It is important that trusts are independent of government: they need to be free to challenge policy.
"Appointing a former Labour MP to this kind of well-paid position calls into question their independence."
Mr Griffiths replaces Russell Hopkins, who received £30,000, according to the trust's annual report for 2003/04.
Mr Griffiths told the BBC News website he had undergone "exactly the same appointment procedure as anybody else," and there had been an independent assessor on the committee which made the decision.
"Given my own experience in the health service I feel quite happy that my appointment will be up to any scrutiny."
Mr Griffiths, who will be chairman for four years, said he was happy to let the ombudsman look at the process which led to his role.
He also pointed out that he was being appointed to an NHS post, rather than to a private health company.
A Welsh Labour spokesperson said: "This is a smokescreen to cover the nationalists' internal problems.
"Are they saying that no Labour figures should be allowed to serve public bodies, and would they start applying the same rule to Plaid Cymru?"
The trust has been asked to comment.