Almost nine months into a two-year trial, Victoria's sick pay guarantee has paid out about $19 million, receiving more than 80,000 claims from casual and contract workers without sick leave entitlements.
Eligible casual and contract workers in the state were able to claim five days of paid sick leave a year from last March under the pilot program, dolled out at the national minimum wage.
About 150,000 workers in the hospitality, security, retail, cleaning, aged and disability care sectors were expected to be covered but just 55,000 have registered so far.
Employment Minister Ben Carroll said the Andrews government was open to expanding eligibility criteria but noted the scheme was initially targeted at the most vulnerable workers.
"There certainly is scope to expand the scheme," he told reporters at a retail store in Fitzroy on Thursday.
"We have invested between $200 and $250 million in the scheme; a lot of that goes towards the infrastructure we have put behind the scheme to make it ... simple and easy."
When the trial was first unveiled by Premier Daniel Andrews, employer groups feared the government would eventually pass the cost of funding the program on to businesses beyond the two-year trial.
Mr Carroll said the government was working through a long-term solution to funding the scheme beyond March 2024, and wouldn't rule in or out a tax or levy on businesses.
"We will make all of those assessments ... at the end of the trial," he said.
"I don't want to pre-empt anything except to say we're at the halfway mark, the data is very strong, it's been well resourced, well funded ... and we'll have more to say in another 12 months when the scheme gets to its final months."
Any unspent government funding from the trial could make it less likely businesses face a new tax or be used to expand the scheme to other vulnerable workers, Mr Carroll said.
"There are some one million Victorians out there who do not have paid entitlements if they're sick," he added.
"So in many respects we're scratching the surface here with 55,000 registrations."
