Newly appointed foreign minister Kevin Rudd is acting as Australia's prime minister in exile, opposition counterpart Julie Bishop says.
Prime Minister Julia Gillard gave Mr Rudd the portfolio on Saturday, after deposing him from the top job in June.
The Queensland frontbencher and his Labor colleagues will be sworn in to their new roles in Canberra on Tuesday.
Then he'll head to the US later this week to meet senior officials in the Obama administration and attend the UN General Assembly.
Ms Bishop said Mr Rudd appeared to be picking up where he left off as prime minister.
"I understand that the UN requested world leaders to attend the General Assembly meeting," she told ABC radio.
"Mr Rudd clearly sees himself as Australia's prime minister in exile."
While it was appropriate for the foreign minister to travel abroad and attend high-level meetings, Ms Bishop said Mr Rudd's hasty departure showed there were tensions within the Labor Party.
"What possible authority can Julia Gillard assert over Kevin Rudd?" she asked.
"The relationship between the prime minister and the foreign minister s fractured at best."
Opposition Leader Tony Abbott is expected to announce his frontbench later in the day or on Wednesday.
