The Scottish Opera leak row has exposed a "gaping hole" in the scrutiny of ministers, the Tories have claimed.
Jack McConnell has denied leaking confidential information
The standards commissioner said it was not within his remit to investigate complaints about ministerial actions.
First Minister Jack McConnell has been accused of leaking confidential information about a rescue package for Scottish Opera - a claim he denies.
The Conservatives have now asked Holyrood's standards committee to investigate the row.
The Tories had wanted Dr Jim Dyer to look into the claims that Mr McConnell leaked information to a Sunday newspaper.
However, the commissioner issued a statement on Monday in which he clarified his powers.
"The remit given to my post by the Scottish Parliament does not include the investigation of complaints about ministerial actions," he said.
"There is a separate ministerial code governing these, issued by the Scottish Executive in February 2002.
"My remit involves investigating complaints that a member has breached the code of conduct for members."
This covers ministers' actions when they are, for example, pursuing matters on behalf of constituents.
However, the ministerial code applies when they are acting as members of the Scottish Executive.
Tory culture spokesman Jamie McGrigor said this code was overseen by the first minister's office.
"This appears to leave a gaping hole in procedures that govern the conduct of ministers in general and the first minister in particular," he said.
He has now written to convener Brian Adam asking the standards committee to look into the row.
Mr McGrigor said the allegations made by Scottish Opera's chairman Christopher Barron, who sent a letter to staff claiming that Mr McConnell was "clearly involved" in the leak, and Mr McConnell's "lack of clarity" were both worthy of investigation.
He also wants the culture committee to look into the "precarious" state of Scottish Opera's funding.
The Scottish National Party has called for a full inquiry into the row.
Chief whip Bruce Crawford said such a step was required to "lift the lid on the nature and culture of the McConnell government".
Mr McConnell has denied leaking confidential information and dismissed calls for an inquiry into the allegations as "ridiculous".
Culture Minister Frank McAveety said that the information which appeared in the Sunday Herald article was already in the public domain.
Meanwhile, it has emerged that MSPs who said they were reporting the first minister to the commissioner may themselves have broken the rules as they should have kept any complaint private.