Australia's Prime Minister Scott Morrison is campaigning to block a bill that would let sick asylum seekers in offshore centres get treatment in Australia.
Mr Morrison said the bill would "take control from the government", and "unleash a world of woe".
Australia has sent asylum seekers who arrive by boat to detention centres on the Pacific islands of Nauru and Manus.
Its tough immigration policy has been repeatedly criticised.
"The problem with the bill is it...