Hundreds of protection visas revoked

Hundreds of Australian protection visas have been torn up by officials in the past three years and the rate of cancellations shows no sign of slowing.

Immigration officers have revoked 278 protection visas since July 2014 after fresh information has come to light about identity issues or travel patterns.

Roughly two-thirds of the cancellations have stemmed from individuals travelling back to countries where they claimed they were being persecuted.

The remaining one-third related to incorrect identities or wrong information submitted in original claims lodged with Australian authorities.

The rate of scrapped protection visas has grown rapidly over the past three years, a Senate hearing in Canberra was told on Tuesday.

* 2014-15: 25 cancellations;

* 2015-16: 85 cancellations; and

* 2016-17: 168 cancellations (as of May 16).

Officials are considering whether to cancel the protection visas of another 335 people.

Veteran coalition senator Ian Macdonald is disgusted by the numbers.

"It just does sicken me and many others that whilst there are many genuine refugees there are also many who have rorted the system," he said.

"Does it mean that others, who are genuine refugees sitting out their time in squalid refugee camps around the world, who are waiting their turn to come to Australia, have been queue-jumped by these people who have lied?"

Immigration department boss Michael Pezzullo said the nature of undocumented arrivals into the country raised the possibility a percentage of people were not who they claimed to be.

"Yes, they (those whose visas were later cancelled) would have displaced genuine refugees," he said.