Next week Ms Sturgeon will become the first Scottish First Minister to contribute a regular column to a newspaper when she submits her first weekly article to the Daily Record.
Her new role as a newspaper columnist led to the warning from Tory deputy leader Jackson Carlaw.
The ministerial code says ministers may contribute to a book, journal, newspaper (including the letters pages), blog or other similar social media provided that publication will not be at variance with Ministers‟ obligations to Parliament.
The code adds that the article should not interfere with their duty to observe the principle of collective Ministerial responsibility and that it does not bring the Government into disrepute.
It adds that no payment should be accepted for such contributions.
Mr Carlaw said: “It’s odd that just as Nicola Sturgeon becomes the most polarising figure in Scottish politics, the Daily Record should reward her with a weekly column.
“People will be curious if the First Minister will actually be writing it, or if that task will be delegated to a civil servant or party hack to come up with weekly pearls of wisdom.
“It is unusual to say the least for a head of government to lead such a column.
“Even her predecessor - not known for his modesty - waited until his best days were behind him.
“Nicola Sturgeon will have to be careful not to breach the ministerial code, bypass parliament with major announcements or have her government give preference to one newspaper over another.”
A Scottish Government spokesman said: “The Ministerial Code is clear that Ministers may engage in writing for newspaper publications and the relevant safeguards set out are all being observed. As such, this is entirely in line with the code’s provisions.”