The justice secretary has criticised the Scottish Police Authority's (SPA) attempt to reinstate the country's chief constable.

Phil Gormley has been on special leave since September while he is under investigation by the Police Investigations and Review Commissioner (Pirc) into alleged gross misconduct.

The SPA unanimously decided on November 7 to reinstate Gormley and did not inform Matheson of the change until two days later, just 24 hours before he was due to return to work.

Matheson called on the police board to reconsider its decision during a meeting with the organisation's then-chairman Andrew Flanagan.

Mr Flanagan then reversed the decision and placed Mr Gormley back on special leave.

The row only became public following the leaking of a letter from the police officer's lawyer to The Herald.

Mr Gormley denies any wrongdoing and his lawyer has described the minister's intervention as having "no lawful basis".

The justice secretary told MSPs at Holyrood on Wednesday that he pressed Mr Flanagan to confirm if "due process" had been followed but he was "unable to give me those assurances".

"Key parties had not been consulted," said Matheson. "In particular, the Pirc had not been asked for her view on whether the chief constable's return at that point could impact on her investigations."

He added: "Another area of particular concern was that there did not appear to be a robust plan in place to protect the well-being of officers and staff who had raised complaints or who may have been asked to play a role in the investigations.

"A number of these officers and staff were based at the Tulliallan headquarters in close proximity to the chief constable and were in positions where they could expect to be dealing with the chief constable in the course of their work."

Matheson said he asked the SPA to reconsider its decision and, if he had not, the criticism from opposition parties would have been "harsher" and indeed "justified".

The minister's explanation was not enough to silence those who have accused him of interfering with the independent watchdog.

Scottish Conservative shadow justice secretary Liam Kerr said: "This is an almighty mess, and one of the SNP's own making."

He added: "The Nationalists can't look elsewhere for blame. They are in sole charge of justice and it's up to them to run a police force that is efficient, effective and free from the scandal we've seen in recent months."