Japan fell into a trade deficit in October, data showed Monday, as a stubbornly strong yen, softening global demand and disruption from deadly floods in Thailand helped slow its post-quake recovery.

October exports dropped off while imports kept soaring, leaving a deficit of 273.8 billion yen ($3.6 billion), the finance ministry said.

"Exports weakened due to a slowing global economy while imports kept rising due to higher natural resources prices. Japan slipped into the red in a worrisome way," said Daiwa Institute of Research economist Satoshi Osanai.

"Trade risks have taken their toll. The outlook for exports is murky," he said. "The economy will be recovering at a slow pace in the long term, but is currently at a standstill."

The October deficit was the first in two months, reversing a year-before surplus of 812.6 billion yen. Economists had expected a surplus of 55.6 billion yen, according to a survey by Dow Jones Newswires and the Nikkei daily.

Japan returned to a trade surplus in September as auto production recovered to levels seen before the devastating March earthquake and tsunami hit output.

But flooding in Thailand has hit the operations of automakers and electronics firms due to damage to facilities and shortages of components, with Thai plants forming a key link in manufacturers' supply chain.

"The floods have caused parts shortages in Japan, and reduced exports from Japan to automakers factories in Thailand," said Capital Economics in a research note. Toyota and Honda withdrew forecasts as they assess the damage.

Overall exports fell 3.7 percent to 5.51 trillion yen, the first drop in three months, while imports rose 17.9 percent to 5.79 trillion yen, logging a year-on-year rise for the 22th consecutive month on higher oil and gas costs.

Asia-bound exports fell 6.6 percent with shipments to China, the biggest market for Japanese products, plunging 7.7 percent and those to Thailand down 5.1 percent.

The Bank of Japan last week warned that Japan's growth was slowing amid uncertainty abroad and market turmoil caused by the eurozone crisis as well as the flooding in Thailand.

Japan posted an annualised growth rate of 6.0 percent in the July-September quarter as companies ramped up production to make up for quake-hit output, but analysts say the strong yen and global slowdown will weigh on the recovery.

Concerns have deepened over the eurozone debt crisis, which has sparked yen buying as a safe haven, helping push the Japanese unit to post-World War II highs against the dollar, eroding exporter profits and making goods less competitive.

Monday's worse-than-expected data "may signal that exports may continue to fall in coming months," said Takeshi Minami, chief economist at Norinchukin Research Institute.

Minami told Dow Jones Newswires that he was concerned about a fall in exports to Asia, a key destination for Japanese products.

The drop might reflect a slowing in the Chinese economy, the effect of the flooding in Thailand, and the yen's strength, he said, adding a downward trend for exports could strengthen after the start of next year.

"Exports of electronic devices plunged due to a global slowdown while those of ordinary machinery fell due to lower demand from the rest of Asia," Daiwa's Osanai said.

Japan has also been importing more fossil fuel to run thermal power plants in compensation for nuclear reactors that have gone offline after the Fukushima nuclear accident triggered by the March quake.

With the European Union, Japan's trade surplus dived 47.1 percent to 100.2 billion yen, the lowest since 1979 for the month of October.

The trade surplus with the United States fell 14.5 percent to 389.5 billion yen.