Former Japanese Prime Minister Aso Taro has called for a stronger partnership between Japan and the United States as China ramps up military pressure on Taiwan.

Aso, who is vice president of Japan's main ruling Liberal Democratic Party, delivered a speech at a Washington think tank meeting on Wednesday.

He said, "Now we should pay attention to Taiwan as the next window to be broken," and added, "We need to firmly put international deterrence in place to prevent the number of 'broken windows' from increasing one after another."

Aso stressed that it is important for Japan and the US to work closer together in dealing with China's hegemonic activities and other security threats, and to expand cooperative ties with countries such as South Korea and Australia.

Aso also noted that "a military unification of Taiwan will only disrupt the international order," and "this will not be tolerated."

He said China must be persuaded through dialogue to take responsibility, as a great power, for the stability of the international order.

On ties with the US, Aso urged Washington to rejoin a trans-Pacific trade agreement known as CPTPP.

He said if the US returns to the deal and countries such as South Korea join the framework, "We will see a structure where both security and economic aspects are inextricably linked, and regional stability and prosperity will be further strengthened."