Morrison made his strongest show of support for the facility on a Commonwealth site in Melbourne’s north as Victoria prepares to enter a one-week lockdown.
“We are highly favourable towards this,” he told reporters in Canberra on Thursday.
While the state government made September the earliest date for construction to start, Morrison was confident of bringing that forward.
“We think this can be done actually quicker. That’s one of the things we are working through with them now.”
Victoria has stumped up $15 million to plan the 500-bed Mickleham hub, which would require a $200 million federal contribution.
It’s estimated $700 million from the Commonwealth would allow for it to be increased to 3000 beds.
Morrison stressed the new capacity would be on top of using hotels to isolate returning travellers.
“It’s not in place of hotel quarantine, that’s not what the Victorian government is proposing,” he said.
Melbourne’s coronavirus outbreak, which has so far infected 26 people, is believed to have started from a man being infected while quarantining in an Adelaide hotel.
This is the 17th outbreak from hotel quarantine in the past six months.
Experts have repeatedly urged the prime minister to put in place dedicated fit-for-purpose facilities to take pressure off hotels that were built for tourism, not medical quarantine.
Acting Victorian Premier James Merlino emphasised the hotel quarantine breach when announcing the fourth statewide lockdown.
“If we had an alternative to hotel quarantine for this particular variant of concern, we would not be here today,” he said.
“If we had the Commonwealth’s vaccine program effectively rolled out, we may well not be here today.”
Labor leader Anthony Albanese accused the prime minister of being complacent on establishing purpose-built facilities.
“If we’d have had dedicated quarantine facilities, then you wouldn’t have outbreaks, of which there have been 17, from hotel quarantine,” he told reporters at Parliament House.
“All of the experts indicate that that is appropriate.”
Morrison said the federal government had provided all the immediate support Victoria had requested.
Increased vaccine doses and defence force personnel have been sent to the state.
The federal government has stood up an aged care response team and offered to help Victoria with contact tracing.
It has also opened expressions of interest for up to 900 additional general practices to participate in the national vaccination rollout.
The prime minister said he was hopeful the lockdown will not be required for the full week despite concerns the measures could be needed longer if the situation worsens.