Humza Yousaf announced on Tuesday plans for the Scottish Fire and Rescue Service and more than 100 military personnel to support the ambulance service – which is currently under acute pressure, causing severe waits for patients.
But details of the announcement appeared in the Daily Record hours before the statement was made.
The ministerial code states that announcement should be made to parliament when Holyrood is in session.
Mr Yousaf was rebuked by Presiding Officer Alison Johnstone ahead of Tuesday’s statement, who said if it happened again she would not allow the statement to be made to MSPs and would instead move straight to opposition questions.
He subsequently apologised to Ms Johnstone and the parliament.
Now, Scottish Tory chief whip Stephen Kerr has written to First Minister Nicola Sturgeon, urging her to step in.
“Yesterday, in his statement to Scottish Parliament, it was confirmed by the Cabinet Secretary for Health and Social Care that he leaked the content of his statement to the Daily Record ahead of delivery to parliament,” he said.
“This included multiple important announcements of government policy on tackling the current ambulance crisis.”
He added: “The Ministerial Code exists to ensure that those in the highest offices of Scotland’s public sector are held to an appropriately high standard. I know you value its contents greatly.
“I am therefore writing to you seeking your commitment to investigate this breach and to outline what measures will be taken in response to any possible outcome of such an investigation.”
Following an investigation by James Hamilton QC into whether the First Minister misled parliament in relation to the Alex Salmond inquiry – which found she did not knowingly mislead MSPs – the First Minister said she would step down if she was found to have breached the ministerial code.
“Let me be clear. Had Mr Hamilton’s report gone the other way, I would have accepted it,” the First Minister said, defending herself against a vote of no confidence on March 23.
“Had he found that I had breached the code in anything other than the most technical and immaterial of ways, I would have been standing here right now tendering my resignation, because the integrity of the office that I am so privileged to hold really matters to me.
“The office of First Minister is more important than any temporary incumbent of it.”
Mr Kerr also said he would be writing to the convener of the Standards, Procedures and Public Appointments Committee.