Singapore's state carrier said Tuesday it will suspend half of its daily flights between the city-state and Tokyo as demand weakened following a nuclear scare in ravaged Japan.

Singapore Airlines (SIA) will halt two of its four flights between Changi Airport and Tokyo's Haneda Airport from this Sunday, the airline said on its website.

"Flights SQ635 and SQ636 which operate between Singapore and Haneda will be suspended from 27 March 2011," a post on SIA's main website read.

An SIA spokesman told AFP the suspension was due to a slump in customers going to Japan after a massive 9.0 earthquake and subsequent tsunami hit the country's northeast.

The twin disasters triggered a crisis at a tsunami-hit nuclear power plant some 250 kilometres (155 miles) from Tokyo, where workers have been struggling to bring overheating reactors under control.

"We are seeing weakening demand in and out of Tokyo due to the situation in Japan," he said.

Kyodo News on Tuesday reported that smoke and steam were again rising from damaged reactors at the troubled Fukushima plant.

White steam-like vapour was seen rising from the number two reactor and what looked like white hazy smoke from the number three reactor, Kyodo said, adding that efforts to spray water and restore electricity had temporarily stalled.

Abnormal levels of radiation were also detected in shipments of certain vegetables and milk from four prefectures near the plant, fuelling public anxiety about contamination from a radiation leak.