Government Services Minister Linda Reynolds said the government would review any decisions by the independent regulator before committing to a pay rise for aged care workers.

"(The government) will wait for (the Fair Work Commission) to do their work. They'll make a determination, we will review it and then we will take whatever position we do after that review," she told a Senate estimates committee on Friday.

But the prime minister says the government will implement the commission's recommendation.

"It's impossible to know what that (decision) is," Scott Morrison told reporters in Sydney.

"The Fair Work Commission finding has to be honoured and it will be."

Greens senator Janet Rice said it was surprising the government hadn't budgeted for the pay rise when it knows the commission will be making a recommendation.

"(The government) didn't see any need to put any form of contingency in the budget to cover those increased costs," she said.

"It's pretty evident, given what we know about the low wages of aged care workers who work tirelessly and are paid a pittance, that there will be recommendations."

But Senator Reynolds said the government can't predict what those recommendations will be.

"We are many things ... but we're not mind readers in terms of what the Fair Work Commission will determine and we'll (budget) that at the appropriate time," she said.

Health department officials also confirmed they have not yet made a submission to the commission on a pay rise for aged care workers.

"We expect to be asked for a submission ... in general terms there is a case for (a wage rise)," Health Department head Brendan Murphy told the committee.

Finance Minister Simon Birmingham said the commission will have all the information when making their decision.

"We're not going out there making any sort of promises ... about what that decision will be, we back the independence of the umpire to make that call themselves," he told reporters in Canberra.

"We'll always sit down and work with the (aged care) sector to ensure their sustainability ... we would receive the details of whatever the Fair Work Commission decides and then work through it with the sector."

Meanwhile, only half of aged care providers have had the $400 bonus per worker promised by the government approved.

The Health Department said 499 of 807 aged care service providers have had their applications for the payment approved since the bonus was announced earlier this year.

But it could take between three and six months for an audit to determine if workers haven't received the bonus, Health Department official James Benson told the committee hearing on Friday.

Before then, it will be up to workers to alert the department if they haven't received it.

Senator Rice said this shows the government is not following through on its promises.

But Dr Murphy said providers want to do the best thing by the workers and will apply for and pass on the payment.

Labor made aged care a key plank of its budget reply on Thursday, pledging to improve the pay of aged care workers and making a formal submission to the commission in favour of a rise.

Australian Associated Press