MELBOURNE, AAP – Compliance and vaccination blitzes have been launched across the Victorian building industry, with the sector put on notice it could lose its ability to keep working during COVID-19 lockdowns.

Treasurer Tim Pallas announced the four-week enforcement blitz would begin on Monday, declaring the construction industry stood at a “critical juncture” as one of the few sectors still operating.

“We’re seeing increasing case numbers coming out of that industry linked to this workforce,” he told reporters.

“What’s become clear to us is that the construction industry remains a major source of transmission.”

Of the 3507 active cases in the state, 13 per cent are directly linked to construction sites.

Victorian authorities are particularly concerned by cases geographic spread, with the average infected construction worker living about 20 kilometres away from their workplace.

That compares to 4km for the average case in the outbreak.

The treasurer spoke with industry leaders as recently as Sunday night to convey the sector was in a “precarious position” and could lose its authorised worker status.

“We’ll do everything we can to ensure the construction industry can continue in a COVID-safe way,” Mr Pallas said.

“But the entire industry – employers, unions – are on notice. We’ve had significant transmission on building sites, and we simply cannot afford not to act if that continues to grow.”

While the majority of sites are following rules, including workers donning masks, Health Minister Martin Foley said it was clear the industry needed to improve.

“It doesn’t take much for this highly infectious Delta variant to get from a highly mobile, younger, under-vaccinated workforce into outer suburbs, into the families and communities of those suburbs, and, as we have seen, into the regions,” he said.

Nearly 6000 checks have already been carried out, and Mr Pallas said WorkSafe inspectors would now adopt a “zero tolerance” approach.

From July 1, on-the-spot fines for authorised worker breaches increased to up to $1817 for individuals and up to $10,904 for businesses.

Opposition health spokeswoman Georgie Crozier said the state government was playing “catch up”, and should immediately introduce rapid antigen testing on building sites.

“This is the ideal scenario where you would put rapid testing in place,” she said.

In concert with the enforcement blitz, four major Victorian vaccination centres will allow construction workers to get a jab without a booking from Monday until September 26.

A further 20,000 further priority Pfizer appointments will also be made available to construction workers at all state-run hubs, except for drive-throughs.

Melbourne’s large-scale construction workforce is currently capped at 25 per cent, but it was previously announced that figure would double once 90 per cent of workers have had one vaccine dose.

The Victorian Chamber of Commerce and Industry welcomed both the compliance crackdown and vaccination push, but wants “greater clarity” on how the 90 per cent vaccination rate will be documented.