Japanese MP, Akihisa Nagashima, told more than 200 representatives at the 28th Asia-Pacific Parliamentary Forum in Canberra, the world should not “sit on the sidelines” against Beijing’s emerging influence in the region. China claims vast areas of the energy-rich waters and has established military outposts on artificial islands. The contested waters are also believed to contain large quantities of oil and natural gas.
Mr Nagashima, who also sits on the National Security Committee, told representatives from more than 30 countries, including Russia and the US, the actions of Beijing poses a threat to regional order.
The 57-year-old said: “China forcibly conducted large-scale rapid reclamation of maritime features which are being converted into military outposts.”
He added: “We should not sit on the sidelines in the face of these developments, if these kinds of actions are repeated, condoned and left unaddressed, they could completely subvert the existing regional order.
“We should reaffirm the very principle that any unilateral action by force or coercion to change the status quo is unacceptable.
“I cannot over-emphasise the critical importance of the hard earned set of rules and principals for the stability and prosperity of the Asia Pacific.”
The South China Sea is also one of the busiest shipping lanes in the world.
A 2015 US Department of Defence report found an estimated $5.3 trillion (£4 million) worth of goods are shuttled through the South China Sea on an annual basis.
Under international law, a large part of the South China Sea comes under Vietnamese sovereignty.
However, Beijing disagrees and says that the entire waterway up to the coasts of the Philippines, Malaysia and Taiwan belongs to China – a claim rejected by an international court of arbitration in 2016.
The South China Sea has also been a major source of conflict between Beijing and Washington.
Jens Stoltenberg, Secretary General of NATO highlighted the growing influence of China across the South China Sea, other continents and even Space.
Mr Stoltenberg told US network CNBC: “What we see is that the rising power of China is shifting the global balance of power and the rises of China.
“The economic rise, the military rise, provides some opportunities but also some serious challenges.”