Chen Shui-bian, Taiwan’s president, has suggested his country could “freeze” its current constitution and adopt a new one, a move likely to re-ignite tensions with China.

Speaking to the Financial Times, Mr Chen said that defining the scope of Taiwan’s sovereignty and territory was “extremely serious, complicated and sensitive, but also extremely important”.

The remarks indicate that Mr Chen intends to challenge Beijing further before he steps down in May 2008.

China retains a threat of war against the self-ruled island in case it formalises its de-facto independence. Past moves by Taiwan to amend its constitution – in place since 1947 – have provoked stern warnings from Beijing.

Altering Taiwan’s constitution would be difficult since any change would require a three-fourths majority in the opposition-dominated parliament. A change would also require approval by at least 50 per cent of the electorate in a referendum.

However, Mr Chen pledged to put constitutional change at the centre of the agenda for his remaining time in office. “I must pursue three big movements [including pushing for] a new constitution which truly fits Taiwan,” he said.

Mr Chen’s comments indicate he could adopt a more audacious course in strengthening Taiwan’s separation from China before he steps down, an approach which would unsettle cross-Strait relations after more than two years of relative quiet.

Mr Chen triggered warnings from China and the US in late 2003 and again in early 2004 when he first proposed a new constitution and pushed for Taiwan’s first island-wide referendum.

His remarks appear designed to regain support among Taiwanese nationalist voters, a group his ruling party badly needs to win over before a series of forthcoming elections.

Taiwan’s current “Republic of China” constitution refers to the country’s territory only as “existing national boundaries” rather than spelling out precisely what comprises the national territory. However, since it was written in China after the second world war for all of China, it is widely understood to refer to the then Chinese territory, which stretched as far as Mongolia.

Mr Chen said Taiwan should discuss the idea of a “Second Republic” – a concept raised by one of his former pro-independence advisers – to free the country of what he called an “absurd and unrealistic” definition of sovereignty, without openly provoking China.

“[Under this concept] the current constitution would be frozen, and a new Taiwan constitution would be written,” he said. “Freezing the [Republic of China] constitution also means keeping some kind of a link to the [old] ROC constitution and not cutting it off completely.”

The preamble to a new constitution could address the territory of Taiwan, but the relevant sections of the old constitution defining the territory would not be touched, thus avoiding a change to the status quo, Mr Chen said.

The ideas discussed by Mr Chen represent ways technically to honour his previous commitments not to declare Taiwanese independence.

But the president made clear that he feels no more than formally bound by these commitments: “We are not breaking these commitments. But Taiwan still wants to continue to walk down our own path of democracy, of freedom, of human rights, and of peace.”