A Senate committee is currently investigating the outsourcing of government services to private contractors.

Jason Ward, from the Centre for International Corporate Tax Accountability, said there was a shocking lack of accountability around companies with government contracts in Australia.

Mr Ward took aim at Bupa, which had a $500 million contract to provide aged care services in Australia.

Bupa had to pay the Australian Taxation Office $157 million earlier this year after settling after a legal fight over its tax.

Despite this, Bupa had recently been given a contract to provide health services for Australia's defence forces.

"Companies like this shouldn't be awarded with public dollars," Mr Ward told the committee in Canberra on Friday.

Mr Ward said current laws required companies with more than $4 million worth of government contracts to have a clean bill of health on tax.

But he said these laws lacked teeth, because companies were only required not to be in a current dispute with the tax office or have current debts over $10,000.

A Bupa spokesman told AAP the firm was committed to complying with tax laws responsibly, ensuring that tax is paid in accordance with applicable laws and practices.

In 2018, Bupa Australia paid $158.4 million in income tax on taxable income of $533.3 million.

The company operated in "highly regulated sectors" overseen by such bodies as the Australian Securities and Investment Commission and the Australian Prudential Regulation Authority, the spokesman said.

One of the changes being scrutinised by the committee is the government's plan to pay a private company to build a digital platform to process the bulk of applications for temporary visas to Australia.

The Department of Home Affairs, which oversees Australia's immigration agencies, says in its submission the move would free up more staff to process "higher complexity and higher risk" applications.

But the Community and Public Sector Union says privatising the visa system would introduce a profit motive to processing.

It also estimated at least 2300 public service jobs across Australia could be lost over the next four to five years as both a direct and indirect result of the changeover.

National secretary Melissa Donnelly pointed to a similar system in the UK which had seen price gouging, delays to drive up premiums and administrative bungles.

"(This) means handing a monopoly to a private provider," Ms Donnelly said.

"This is bad policy and the case for change is short-sighted."

Australian Associated Press