THE Scottish Conservatives have insisted a probe into whether Nicola Sturgeon broke the ministerial code must be published before the Holyrood election.

The party's chief whip Miles Briggs has written to the Scottish Government's permanent secretary Leslie Evans seeking assurances on the matter.

The First Minister has promised MSPs the report by James Hamilton QC will be released on the day it is handed over. 

Mr Hamilton, the former head of public prosecutions in Ireland, is investigating whether Ms Sturgeon breached the ministerial code in relation to the botched handling of harassment complaints against Alex Salmond.

If he finds that she did mislead parliament, opposition parties have said she should step down from her post.

Under election rules, the Scottish Government must announce, before parliament breaks, the dates for material to be published during the campaign.

In a letter to Ms Evans, Mr Briggs said: "I am deeply concerned that a failure to publish in advance of the election purdah, or to name a date in advance for publication during the election campaign, would mean that the report's publication during the election campaign would breach the purdah guidance.

"While I understand the need to allow James Hamilton the space to conduct his work, it is important to the people of Scotland that they are able to read his findings ahead of the election."

Another investigation into the complaints procedure at the heart of the Salmond inquiry, conducted by Laura Dunlop QC, has concluded and is set to be published next week.

In a statement, Mr Briggs said: "The SNP have tried to shut down scrutiny and sweep scandals under the carpet too often throughout the Alex Salmond affair.

"We must see the James Hamilton QC report on ministerial code breaches as soon as possible.

"It is of prime importance that the public receives full transparency on the conduct of the First Minister before they go to the ballot in May.

"We are seeking guarantees that the report will be published, no matter what, at the earliest opportunity.

"It's also vital that the Laura Dunlop QC review of the Scottish Government's harassment complaint procedure is published immediately."

A Scottish Government spokeswoman said: "Mr Hamilton is independent and it is a matter from him when his report is complete. The Scottish Government has no control over that timing.

"Once received by the Scottish Government, however, it will be published the same day.

"The report by Laura Dunlop QC will be published next week, once we have completed ongoing data protection notifications that are required by law."