Australia's medicines regulator has accused United Australia Party leader Craig Kelly of breaching copyright and demanded he cease spamming people about adverse vaccine reactions.

Mr Kelly, who quit the Liberals over his refusal to stop spouting unfounded COVID-19 treatment claims, has engaged in a text message campaign about vaccines.

This includes a message with a link taking people to a database of adverse event notifications for coronavirus vaccines.

Lawyers for the Therapeutic Goods Administration have written to the MP for the Sydney seat of Hughes alleging he's in breach of copyright.

The regulator on Wednesday demanded Mr Kelly "stop distributing incomplete extracts of adverse event reports relating to COVID-19 vaccines which the TGA believes could be seriously misleading".

It alleged the extracts were taken selectively from the TGA's database, removing important information about the reports and the regulator's copyright statement.

"Information on the Database of Adverse Event Notifications cannot be used to identify whether a medicine or a vaccine is safe or has caused the reported adverse event or not," the TGA said.

Further investigation is required before an incident can be deemed related to a vaccine, something the TGA emphasises in its database.

"The extracts disseminated by the United Australia Party excluded this important information at the beginning of the reports as well as the statement indicating that the information is subject to copyright under Australian law," the TGA said.