Six Japanese swimmers have started a 150-kilometre (94-mile) relay swim to Taiwan from a Japanese islet to express gratitude for Taiwan's help after the tsunami, officials said Sunday.

The swimmers started their 48-hour relay swim early Saturday morning from Yonakuni 110 kilometres east of Taiwan, according to the state Central News Agency.

But the swimmers will have to make a detour because of a strong Pacific Ocean current, extending their planned swim to around 150 kilometres, the organisers said in a statement to local media.

The group is scheduled to arrive in Suao, a port in northeastern Ilan county, Monday morning to a grand welcoming ceremony, county government officials said.

Taiwan donated more than 20 billion yen ($2.6 billion) to Japan in the wake of the deadly March earthquake and tsunami, making it one of the top donors.

Taiwan maintains cordial ties with Japan despite its past as a Japanese colony from 1895 to 1945, and despite the fact that Tokyo recognises Beijing over Taipei.

cty/mtp