A Chinese company's renewed efforts to build a  massive project on an island off the Papua New Guinea southern coast have again caught attention, and doubt, as a proxy for Beijing to challenge plans by Australia and the United States to operate a joint naval base on an island north of the country.

Triggering speculation about the plans are fresh reports in Australian media that a Chinese company named WYW Holding has again sought approval from the Papua New Guinea government to build a new industrial island city called "New Daru City" with an investment of $30 billion.

Natural resource rich Papua New Guinea, an archipelago in the southern hemisphere Pacific Ocean, has drawn investment from the U.S., Australia and China, but military activity has been limited. And on Monday, Australian Prime Minister Scott Morrison dismissed as "speculative" reports about New Daru City. 

"I honestly think it's just speculative," said Morrison of Australia's northern neighbor. "It's just people flying some kites and I'm not going to overreact to the noise that is flying around out there."

"I speak pretty regularly with the Prime Minister of Papua New Guinea (James Marape) and we have a very good relationship and he well understands our relationship and the importance of our other partners and I couldn't see Papua New Guinea being terribly hasty on anything like that," according to Morrison.

Papua New Guinea is the largest recipient of Australian foreign aid with Australia-based firms active in oil and gas development and mining in Papua New Guinea.

The mega city was first floated in 2020 in a memorandum of understanding, but has not advanced beyond that stage, according to earlier reports.

The United States and Australia plan to redevelop the Lombrum Naval Base on Manus Island to the north of Papua New Guinea. The facility has been under the control of the Papua New Guinea Defence Force since 1974.