SYDNEY, Australia — The Australian government has warned China against building a military base in the South Pacific following a report that the Chinese had approached the tiny island nation of Vanuatu about establishing an outpost there.

The report on Monday that the Chinese and Vanuatu governments had held preliminary discussions about a permanent Chinese military presence in the former French colony, which is 1,500 miles off the coast of Australia, has raised alarm bells in the region.

But China hit back quickly on Tuesday, with a Chinese foreign ministry spokesman dismissing the report that it was seeking to put a base on Vanuatu as “fake news.” Vanuatu’s government also said that there was no such proposal. And Australia’s prime minister, Malcolm Turnbull, said Vanuatu had assured his government that no such request had been made.