Labor has made an ambitious $1 billion pitch to voters with a pledge to create 100,000 jobs if it wins the November state poll.

Payroll tax relief for companies that give jobs to the long-term jobless and young people is a key policy of Opposition Leader Dan Andrews' employment package, designed to tackle the state's unemployment, which at 6.8 per cent is at its highest rate in 13 years.

But Mr Andrews refused to say how a Labor government would fund the plan on Monday saying it would reveal all of its policy costings before the poll.

And Treasurer Michael O'Brien attacked the policy saying most of the ideas already existed under the Napthine government.