TOKYO (AFP) - Japanese Prime Minister Shinzo Abe on Wednesday left for Southeast Asia on his first overseas trip since winning power, seeking to shore up relationships as a counterweight to an increasingly confident China.

Mr Abe's visit to Vietnam, Thailand and Indonesia is also aimed at strengthening ties with the vibrant economies of the Asean bloc as Japan attempts to reinvigorate its sluggish economy.

The conservative leader, who took office in December, originally said Washington would be his first overseas destination, but scheduling difficulties with a busy US President Barack Obama appear to have scuppered the plan.

Before leaving Tokyo, Mr Abe told reporters that he wished to boost ties with countries that shared common values such as democracy and the rule of law.

"I want to make my first foreign trip this time the start of the Abe government's strategic diplomacy," said Mr Abe, who scored a handsome election win after talking tough on a territorial dispute with China.

"Currently, the strategic environment in the Asia-Pacific region is going through a dynamic change. During this change, having closer relations with Asean countries contributes to the region's peace and stability and is in Japan's national interest," he said.

Mr Abe's 2013 stance is in sharp contrast to his previous stint as premier in 2006 to 2007, when he made China his first foreign stop in a bid to repair ties soured by his predecessor Junichiro Koizumi.

Japan and China are locked in a bitter battle over the sovereignty of the Tokyo-controlled Senkaku islands, which Beijing calls the Diaoyus.

Beijing is also involved in acrimonious territorial disputes with the Philippines and Vietnam over parts of the South China Sea with abundant energy reserves and rich fishing grounds.

During his trip, Mr Abe is expected to deliver a policy speech in Jakarta on Friday, reports said.