Twitter says it will apply warnings to tweets containing misleading information about COVID-19 vaccines and implement a strike system of enforcement that could see users permanently banned for repeat violations.

The social media network started promoting public health information before COVID-19 was declared a global pandemic.

It also aimed to remove demonstrably false or misleading content about the virus that had the highest risk of causing harm.

Since introducing its COVID-19 guidance, it said it had removed more than 8400 tweets and challenged 11.5 million accounts.

With more people looking for authoritative public health information about vaccines as programs are rolled out across the world, Twitter says it will expand the guidance.

Katy Minshall, head of UK public policy, said the company recognised the role it played in disseminating credible health information.

"We continue to work with health authorities around the world - including (Britain's health service) the NHS - to ensure high visibility access to trusted and accurate public health information on our service, including about COVID-19 vaccines," she said.

"Today we will begin applying labels to tweets that may contain misleading information about COVID-19 vaccines, in addition to our continued efforts to remove the most harmful COVID-19 misleading information."

She said the approach built on existing work to guard against false claims about the safety and effectiveness of inoculation.

There have been concerns that public distrust of vaccines could jeopardize programs.

Surveys and data show varying levels of willingness to receive a shot according to country and demographic group.