The justice secretary may have acted "unlawfully" during his involvement in the chief constable's period of special leave from Police Scotland, Ruth Davidson has claimed.

The Scottish Conservative leader also accused Michael Matheson of trying to "close down questions" over his role in Phil Gormley's employment status.

Davidson raised the prospect at First Minister's Questions on Thursday after it emerged last week a previously unknown meeting was held between the minister and the then SPA chairman Andrew Flanagan in November.

Nicola Sturgeon told MSPs the minister was "right" to make an intervention.

The SPA board unanimously decided to reinstate Phil Gormley, who is on special leave amid accusations of "gross misconduct", but reversed their decision after Matheson questioned if proper procedures had taken place.

Mr Gormley denies all of the accusations made against him.

It has since emerged the meeting was unminuted by civil servants, meaning the only record of it is the minister and Mr Flanagan's version of events.

Mr Gormley's lawyer accused the minister of acting with "no lawful basis".

Davidson also raised the prospect to Sturgeon at Holyrood.

She said: "This week the justice secretary tried to close down questions over his role regarding Police Scotland and the position of the chief constable, and he failed.

"Since then we've had lawyers and senior police officers exchanging further blows, we've had more evidence of details being kept from this parliament, and most worryingly we've had an admission that no record exists of the meeting when Michael Matheson intervened over the chief constable's return to work."

Davidson added: "This is about whether the Justice Secretary acted unlawfully by directing the Scottish Police Authority to stop the chief constable coming back to work against their own recommendations."

The Conservative leader described the lack of minutes as "shocking" and added, "It's the SNP's secret Scotland and it stinks."

The First Minister responded: "There is a role for the Scottish Government, there is a role for the justice secretary, in making sure the SPA carries out is functions properly.

"Of course the decisions about the employment of the chief constable are for the SPA.

"That division of responsibility is very clear and well understood.

"Michael Matheson was right when faced with the news that the SPA were inviting the chief constable back to work ... to ask questions such as had Pirc (the Police Investigations and Review Commissioner) been consulted given the ongoing investigation into allegations about the chief constable, had senior command been consulted and had steps been taken to ensure the welfare of any police officer that had raised concerns.

"He wasn't able to be satisfied on those matters and that's why the then chair of the SPA looked at the matter again."