China's top defence official has declared an intention to militarise the controversial Belt and Road Initiative to strengthen ties with South Pacific nations in what analysts warn is a significant challenge to Australia's strategic environment.

Defence Minister Wei Fenghe told a gathering of military chiefs from South Pacific and Caribbean nations in Beijing on Monday that the BRI would provide a "framework" for greater military co-operation, undercutting the communist regime's public insistence it is intended to be a vehicle for peaceful economic development.