The West Australian government has banned residents under the age of 50 from getting the AstraZeneca COVID-19 vaccine.

The decision comes after Prime Minister Scott Morrison late on Thursday received recommendations from the Australian Technical Advisory Group on Immunisation.

The ATAGI recommended the Pfizer vaccine be "preferred" over the AstraZeneca one in people aged under 50, who face a very rare risk of developing blood clots.

WA Chief Health Officer Andrew Robertson said that from Friday, AstraZeneca vaccinations will only be given to those over 50.

"People under 50 who are booked in to receive their AstraZeneca vaccine will have their appointments cancelled," he said in a statement.

People in the 1a and 1b vaccination program cohorts - including health workers - who are under 50 and have already received their first AstraZeneca vaccine, should "not be alarmed" and proceed to their second jab.

"You should not cancel your second vaccination booking," Dr Robertson said.

WA Premier Mark McGowan will on Friday join his interstate counterparts and Mr Morrision for a national cabinet meeting to discuss the national vaccine rollout.