The Jan 13-15 visit is the first to China by an Indian prime minister since Mr Atal Bihari Vajpayee travelled there in 2003.

That visit produced agreements on Tibet and Sikkim, issues of concern to China and India respectively, and led to the flowering of trade ties.

Last year, bilateral trade topped US$30 billion (S$45 billion). Two-way trade is now projected to cross US$40 billion before the targeted 2010 date.

However, while trade and economic ties are accelerating, the two Asian giants have had far less success in moving forward on the key issue that divides them - a boundary dispute that dates back almost five decades.

India says China is occupying 38,000 sq km of its territory in Kashmir illegally ceded to it by Pakistan. Beijing, in turn, claims 90,000 sq km of land in the north-eastern Indian state of Arunachal Pradesh, which is next to Bhutan.

Senior Indian paramilitary officials have complained recently about Chinese incursions along the unsettled border, although the Foreign Office has been far more circumspect about voicing its concern.

Indian analysts say PM Singh's trip, planned for months, comes at a particularly inopportune time for him and the ruling Congress Party.

The government's communist backers have stymied a landmark civilian nuclear deal with the United States that had given the Singh government tremendous political currency abroad but had raised concern in Beijing.

Worse, a string of election defeats in key northern Indian states have weakened the government and turned it into a lame-duck administration.

'The visit is taking place at a very difficult time, especially because China has hardened its position on the territorial dispute,' said analyst Brahma Chellaney of the Centre for Policy Research, a New Delhi-based think-tank.

Still, to create a more conducive environment for the visit, a hundred Indian troops flew last month to China's Yunnan province for their first joint military exercise.

A 'very, very positive' bilateral meeting in Singapore in November between PM Singh and his Chinese counterpart, Premier Wen Jiabao, has also helped matters.

Indeed, some of the atmospherics for that meeting had been set by the warm reception given by Beijing in October to visiting Congress Party president Sonia Gandhi and her son, first-time MP Rahul Gandhi.

Last month, China replaced its envoy to New Delhi. Former ambassador Sun Yuxi was seen as having spoilt the atmosphere for President Hu Jintao's November 2006 visit to India by insisting that all of Arunachal Pradesh was Chinese territory.

During the upcoming visit, PM Singh may also seek unequivocal Chinese support for India to be allowed back into the global trade in civilian nuclear technology and fuel.

China is a key member of the Nuclear Suppliers Group (NSG), which must endorse the India-specific safeguards that New Delhi is currently negotiating with the International Atomic Energy Agency to make the Indo-American deal operational.

In turn, India may signal some sort of willingness to eventually consider a free trade accord with China, which it does not recognise as a market economy.

'In Singapore, China hinted clearly to us that it may be interested in investing in India's nuclear power programme once the NSG clearance is in place,' a senior Indian official said.

velloor@sph.com.sg