The Omicron wave gripping Victoria is costing its economy $30 million a week, a fraction of the losses felt by the state during last year's sixth lockdown.

Treasurer Tim Pallas on Friday revealed the Victorian economy is faring much better in the so-called "shadow lockdown" than it did amid the previous Delta wave.

The state was posting weekly losses of about $800 million during Melbourne's 77-day Delta lockdown, before the city reopened in October after hitting a statewide full vaccination rate of 70 per cent.

Despite the rapid spread of the Omicron variant leaving hundreds of thousands in isolation over the summer, Mr Pallas said the wave's impact on the economy is vastly different.

"All the advice that we have is that it is a substantially lesser event," he told reporters.

"We were losing about $800 million a week out of the Victorian economy (last year). The latest advice I'm hearing is closer to $30 million a week.

"We're keeping a close eye and monitoring that."

The treasurer conceded the wave was still having a "dramatic effect" on some businesses and industries, halting their recovery.

But, more broadly, he insisted the state was making inroads to rebuild after six economy-crippling lockdowns.

"It would be true to say this is not an across the board economic recovery. But an economic recovery is underway. Make no mistake about it," Mr Pallas said.

Meanwhile, Victoria is encouraging hundreds of thousands of public sector workers to get their third COVID-19 vaccine jab by offering half a day's paid leave.

More than 300,000 full-time, part-time and casual teachers, paramedics, police officers, firefighters and other public sector workers will be eligible under the arrangement, which was also used for first and second doses.

Employers will foot the bill, unless the payments amount to a "significant additional cost". Staff can also take accrued sick leave if they have an adverse reaction.

Mr Pallas called on the private sector to "do the right thing" and match the state government's half-day leave pledge for its workers.

The state government hasn't ruled out mandating third doses for some workers, he said, but Chief Health Officer Brett Sutton is yet to be asked to provide advice.

Victoria's third dose rate has risen to 28.3 per cent as a four-day "booster blitz" began at eight state-run hubs on Friday.

Prof Sutton said the blitz was off to a strong start, with 36,000 bookings made over the past four days.

One in four children aged five to 11 have received their first vaccine dose, which could rise to one in three by next week.

The Victorian government is still yet to detail its back-to-school plan but has vowed students will return to classes when term one begins on January 31.

Opposition health spokeswoman Georgie Crozier said parents were crying out for clarity.

"What is the government proposing for teachers, for students, for parents? I think all parents should be very concerned," she said.

Victoria recorded a further 20 COVID-related deaths and 18,167 new cases on Friday, its lowest daily figure since January 5.