Temporary visa numbers soar by one million

The number of temporary visas granted to people entering Australia has soared by one million in just two years, a parliamentary inquiry has heard.

Immigration officials issued 8.7 million temporary visas in the last financial year, up from 7.7 million in 2015/16.

However, the number of temporary visas refused on bad character, national security or identity fraud grounds also increased 46 per cent in the past year.

"To think we've let our guard down in terms of visa integrity would be a misplaced thought," Home Affairs secretary Michael Pezzullo told a Senate committee in Canberra on Monday.

The Department of Home Affairs is investigating partnering with the private sector to revamp its visa processing systems.

Senior bureaucrats have long expressed concerns the department's ageing infrastructure is struggling to keep pace with exponential growth in visa applications.

The federal Labor opposition fears this "outsourcing" of visa platforms could eventually lead to the automation or privatisation of visa decisions.

But Mr Pezzullo insists departmental officers will still be responsible for making visa decisions if the plan goes ahead.