The Australian opposition Labour party immigration spokesman has been denied a seat on a government trip to Manus Island to inspect the offshore refugee processing centre.
Richard Marles had been due to fly to Papua New Guinea on Monday as part of the Immigration Minister Peter Dutton's entourage.
The trip to inspect the Manus facility had been in the pipeline for a month.
However the minister's office informed Mr Marles' office late last week there was no longer room on the government VIP jet and that he would need to make his own travel arrangements.
Labour, Greens and crossbenchers combined in the Senate last week to set up an upper house inquiry into claims that asylum seekers on Nauru were sexually abused.
A spokeswoman for Mr Dutton said Mr Marles recently flew with the minister to Nauru, a courtesy the previous Labour government had not extended to the Liberals in opposition.
Mr Dutton visited the Manus Island detention centre on Monday and met with the PNG Prime Minister Peter O'Neill.