TOKYO (Reuters) - Japan's annual exports in January jumped the most since late 2013 in an encouraging sign a weak yen is finally boosting the nation's all-important export engine and helping the economy crawl out of recession.

The shipments data was followed by the Reuters Tankan survey, which showed both manufacturers and service-sector mood improving in February and over the next three months even as some businesses worried about a deteriorating global outlook.

The 17.0 per cent year-on-year gain in exports marked the fifth straight month of increase, supported by shipments of cars to the United States and of electronics parts to Asia, data by the Ministry of Finance showed.

Ministry officials say exports are on a firm footing, adding that special factors helped boost shipments such as a rebound from last year's Chinese New Year holidays which fell in January, and extreme cold weather which hit the U.S. economy a year ago.

A pickup in shipments - which had been a soft spot in the economy - is welcome news for policymakers who hope exports will offset still-weak private consumption, and cheaper oil prices will spur firms to spend more on wages and investment, generating a virtuous growth cycle.

And as the economy recovers from recession, stronger exports growth would let the Bank of Japan hold off on any additional stimulus.

BOJ Governor Haruhiko Kuroda said on Wednesday he saw no need now to expand monetary stimulus as the bank raised its view on output and exports and stuck to its assessment that the world's third largest economy is recovering moderately.

"The BOJ will wait to see how oil prices may impact people's deflationary mindset, and brisk trade data will encourage Kuroda to stand pat on policy for the time being," said Takeshi Minami, chief economist at Norinchukin Research Institute.

An annual 11.2 per cent jump in export volume suggests that Japanese exporters who have gained hefty profits due to a weak yen are lowering exporting prices to boost shipments, Minami added.

Nissan Motor Co is trying to boost car exports from Japan to benefit from the weaker yen. Honda Motor Co, which has virtually no exports from Japan now, aims to ship abroad about 10-20 percent of its cars built at home.

Exports to the United States rose 16.5 percent on-year in January, while those to Asia, which account for more than half of Japanese exports, grew 22.7 percent, driven by a rush in demand before the Chinese New Year holidays.

In the Reuters Tankan, which closely tracks the BOJ's key tankan survey, sentiment index for manufacturers rose to 11 from 9 in January, led by gains in autos/transport equipment industry.

But managers who responded anonymously to the Reuters poll also said there was lingering anxiety about the global outlook.

"Countries and regions other than the United States remain slow and we are unlikely to escape from such a situation for the time being," a nonferrous metal maker said.