The UK government is monitoring China's increasing military expansion,including revelationsthat China has approached Vanuatu about establishing a military base in the Pacific Islands. Beijing is likely to come under pressure to explain its motives.
The move could see the rising superpower sail warships on Australia’s doorstep.
But Nick Timothy,who served as May's chief of staff until last year,said Beijing's intentions were clear.
"For years the West has treated China as though its intentions were completely benign,"he told Fairfax Media.
"It is becoming better understood,belatedly,that Beijing's global ambitions are not only about economics and commerce but have a geopolitical and security dimension too. We need to be much harder-headed about how we deal with them."
Britain has (FONOP) exercises in the South China Sea,where the military travels within 12 nautical miles of disputed territory that China claims as its own. However Britain sails warships through the South China Sea,which it sees as a way of demonstrating Britain's position without risking a surface military skirmish.
Responding to Fairfax Media's report,Prime Minister Malcolm Turnbull said on Tuesday that Vanuatu had assured Australia"no such request has been made"but he warned any foreign military presence in the Pacific Island nations would be of to Australia.
Conservative MP,who sits on the UK Parliament's Foreign Select Committee,said Australia was"right to be concerned"by what he described as a"potentially significant power projection"by Beijing.
"Authoritarian states such as China and Russia are expanding their military spheres and rubbing up against western nations,"he said.
'This is a that is going to continue - from the Artic to the Pacific.
"Australia,the US and states such as the UK need to focus more on how we can work together to counter this trend,not in a way that escalates tensions but in a way that shows determination for open and free societies to support each other."
Australia's outgoing high commissioner to the UK and former foreign minister,Alexander Downer,has previously that the global coalition of Western democracies could be left weakened if Britain's already-fractious Brexit negotiations with the EU turn acrimonious and it is for a rules-based global order.
Singling out the the rise of China as the"greatest single geo-political issue of the era,"he said it was in Australia's interests for a"strong and decisive Western world".
Rory Medcalf,head of the Australian National University's National Security College,said any"initial"Chinese footprint in the Pacific Islands would be small but would constitute a"negative turning point in Australian defence policy".
"There is nothing between Vanuatu and Australia except the Coral Sea,"he wrote in a for the Lowy Institute.
"The PRC is currently not a source of direct military threat to Australia but defence planners have to consider worst-case scenarios,and China is a source of risk - a potential threat if it chose to be,and if regional strategic dynamics were to keep deteriorating,"he wrote.