Scott Morrison will hold twice-weekly meetings of the national cabinet for the “foreseeable future”, as the government battles to get its slow and problem-laden vaccine rollout back on course.

The Prime Minister says he has asked national cabinet and health ministers to “move back to an operational footing” to tackle the program’s challenges.

This comes as the rollout is being recalibrated following the medical advice restricting the use of the AstraZeneca vaccine to people over 50. Morrison has refused to set a target date for having all those eligible and willing vaccinated with at least one shot, after abandoning the government’s previous October target.

Morison’s action on the national cabinet and his comments are his bluntest admission so far of the program’s difficulties, which started from its beginning and have multiplied ever since.

“There are serious challenges we need to overcome caused by patchy international vaccine supplies, changing medical advice and a global environment of need caused by millions of COVID-19 cases and deaths,” he said in a statement.

“This is a complex task and there are problems with the programme that we need to solve to ensure more Australians can be vaccinated safely and more quickly.”

He said the federal government was trying to deal with its issues “and I have been upfront about those”.

But states and territories were also tackling their own issues, he said.

“Working together we are all going to be in a better position to find the best solutions.”

The federal government has taken the main responsibility for the rollout, but it does not have the states’ experience at service delivery and this has added to the problems.

The new regime for national cabinet meetings will start on Monday and continue “until we solve the problems and get the programme back on track”. It has been recently meeting only about monthly.

Meanwhile, a second person has suffered a blood clot after receiving the AstraZeneca vaccine.

A woman in her 40s is recovering in the Darwin Hospital after being transferred from a regional hospital in northern Western Australia. The Western Australian Health Minister, Roger Cook, said the woman was in a stable condition in ICU.

Earlier a man in his 40s in Melbourne developed a clot after receiving the vaccine.

Last week Morrison announced the Australian Technical Advisory Group on Immunisation had advised against giving AstraZeneca vaccine to people aged under 50.

On Monday more than 56,000 doses of Pfizer and AstraZeneca vaccines were administered.