'It's a deterrent': Treasurer defends spending $185 million to reopen Christmas Island

"What we've done by reopening Christmas Island is send a deterrent to people who would try to game the system," Mr Frydenberg told the ABC's Insiders program on Sunday.

"Whether it's in our turnbacks, whether it's in offshore processing or whether it's with Christmas Island, we are absolutely focused on ensuring there is no repeat of Labor's disastrous border protection policies."