Queensland public servants have been warned to watch their political commentary during the election campaign in case it is mistaken for "official policy".

In what at least three health workers told Fairfax Media was a first, Queensland Health Director-General Ian Maynard sent a missive to employees requesting they think before they post or speak on political issues.

In the emailed note Mr Maynard said he was providing "general guidance" about "your right, as a private citizen, to participate in the political process, including commenting on political/government policies and activities or running for office".