China said on Sunday it was increasing military spending by 7.2 percent -- the fastest pace in four years -- to 1.55 trillion yuan ($225 billion), at a key meeting of its rubber-stamp parliament.

Speaking to lawmakers, Taiwanese Defence Minister Chiu Kuo-cheng said: "It seems the other side is preparing for the use of force if necessary in the future."

Taiwan lives under constant threat of an invasion by China, which views the democratically ruled island as part of its territory to be seized one day, by force if necessary.

Beijing has ramped up pressure in the last year, staging huge military drills around Taiwan in August after then US House speaker Nancy Pelosi visited the island.

On Monday, Chiu said future high-level visits by foreign dignitaries could be a catalyst for invasion.

"I think they are waiting for a good reason to send troops, such as high-level visits from other countries to Taiwan or too-frequent activities between our military and other countries," he said.

The minister said Taiwan was "making advance preparations" for incursions deeper into waters around the island than have been the norm in recent years.

A Chinese foreign ministry spokesperson dismissed Chiu's remarks during a briefing on Monday.

"Taiwan is a part of China and therefore Taiwan has no defence minister," said Mao Ning.

"Both sides of the Taiwan Strait are Chinese territory. China will take firm measures to safeguard its sovereignty and territorial integrity."

At the National People's Congress in Beijing on Sunday, outgoing Chinese Premier Li Keqiang reiterated the mainland's opposition to Taiwanese independence, calling for "peaceful reunification".

On Monday, Taiwanese Premier Chen Chien-jen asked China to "respect" Taiwan.

"Cross-strait relations should be conducted under the principles of rationality, equality and mutual respect so that the relations can develop positively in a healthy and sustainable manner," he said.