China has lodged an official complaint with Australia after a Turnbull government minister attacked Beijing's aid program in the Pacific.
International Development Minister Concetta Fierravanti-Wells criticised China's assistance to tiny Pacific island nations for building "white elephant" projects and "roads to nowhere".
She also expressed concerns about the sustainability of China's loan arrangements with the island nations.
In 2009 Tonga's debt to China was $US100.4 million ($A132.9 million), which was equivalent to one third of its national income.
The Chinese foreign ministry defended the aid program, saying it respected the will of Pacific island governments and the development needs of their people.
"The remarks made by the Australian official show scant regard for the facts and are nothing but irresponsible," a spokesman said.
"The Chinese side has lodged representations with the Australian government on this."
He said assistance China provides has significantly fuelled the economic and social development of the countries and was warmly welcomed.
Labor's foreign affairs spokeswoman Penny Wong said the comments demonstrated the government's clumsy approach to foreign policy.
The Lowy Insitute estimates China has poured $2.3 billion in aid to the South Pacific since 2006.
The Institute's Pacific Islands program director Jonathan Pryke said the senator had made a legitimate point but the value of projects had to be assessed on a case-by-case basis.