Premier Daniel Andrews told his party’s annual conference in Melbourne on Saturday morning that 234 Victorians had lost their lives at work in the past decade and that Labor was determined to change workplace culture in the state.

Mr Andrews told the 600 delegates that bosses whose negligence cost workers their lives would also face fines running into the millions of dollars under a reformed Occupational Health and Safety Act.

The Age revealed on Saturday that Labor also intended to make Victoria the first state to put bosses in jail for deliberately underpaying their workers.

But Mr Andrews promised the conference even more industrial reform if Labor wins November’s state election, promising to hold to account employers for the lives of their workers.

The laws will cover suppliers, contractors, site visitors and even passers-by,  the Premier promised.

“We’ll amend the OH&S; Act, so that if an employer’s negligence causes death – they will be held to account,” Mr Andrews said.

“That doesn’t just mean thousands of dollars in fines, that means millions.

“And it’ll mean jail time – up to 20 years.

"We’ll make sure these laws extend to staff and beyond.

"They’ll cover a visiting supplier.  A routine maintenance worker, or three innocent people walking down a busy street, on the edge of our city."

In 2013 three pedestrians were killed when part of a hoarding wall on a Carlton building site collapsed onto Swanston Street.  The site's then owner, developer Grocon, was fined $250,000 over the incident after it pled guilty to a workplace safety charge.

Construction union the CFMMEU had been preparing a push on day two of the Labor conference to bring industrial manslaughter onto the party's policy platform.

Union leader John Setka said he was surprised to hear Mr Andrews' announcement, which the Premier is understood to have developed with Victoria's Trades Hall.

Mr Setka said a "deterrent" was needed to stop employers taking risks with their workers' lives.

"It was a surprise, but at the same time I'm very happy with it" Mr Setka said.

"I'm hoping that this will save a lot of heartache for a lot of families, it will save a lot of lives."

Deputy Victorian Liberal leader David Hodgett said his party would form a position on industrial manslaughter once it had seen the detail of the proposal.

“We believe that anyone, anyone, should expect to be able to go to work and come home,” Mr Hodgett said.

“Let’s have a look at the detail on this and we’ll form a position on it.”

Mr Hodgett accused the Premier of “hypocrisy” on wage theft, with the Liberal deputy claiming Labor MPs had “ripped off their employer” in the ‘red shirts’ affair.

In March, Victorian Ombudsman Deborah Glass found Labor had misused almost $400,000 in public funds while campaigning to win the 2014 election.

“Of course we support people getting paid fairly or getting their entitlements bit does this extend,” Mr Hodgett said.

“He talks about people getting paid fairly but he doesn’t look at the other end of the scale, where 21 Labor MPs ripped off the Victorian taxpayer for thousands and thousands of dollars ... they should be in jail.”

Federal Workplace Minister Craig Laundy said the Fair Work Act already addressed underpayment of wages and he does not think it needs to be criminalised.

"The vast majority of employers do the right thing," he said on Friday in response to Labor's wage theft proposal. "But anyone that doesn't, yes we should fine them and get backpay.

Mr Laundy said most employers the Fair Work Ombudsman identified in a recent hospitality industry blitz had made genuine administrative mistakes, which would be better addressed through education, not prison sentences.

"Information is the key here, not throwing people in jail," he said.

with Anna Patty