Papua New Guinea has announced a ban on Australians travelling to Bougainville, after Canberra said it plans to build a diplomatic mission on the island.
Despite the Australian Foreign Minister, Julie Bishop, saying she consulted PNG and notified the Prime Minister last week, the PNG Foreign Minister, Rimbink Pato, says the move is "mischievous" and "outrageous".
Bougainville, a self-governing region of PNG, is working towards holding a referendum on independence in the next five years.
The country is the largest recipient of Australian foreign aid, receiving 381.4 million US dollars.
PNG's Prime Minister, Peter O'Neill, visited Sydney last week and says there was no consultation and nothing had been agreed.
Mr Pato says the ban has immediate effect.
It will not affect Australians residing in Bougainville on work and permanent resident visas.
The ban will apply to all Australian passport holders who intend to visit Bougainville on tourist, business and other short-term entry visas.