Record tumble in Japan machinery orders casts doubt on Abenomics

* Dec core machinery orders -15.7 pct m/m vs forecast -4.1 pct * Core orders +1.5 pct q/q in Q4, seen -2.9 pct in Q1 * Capex holds key for success of 'Abenomics', sustained growth * Companies hoard cash as remain wary of boosting spending By Tetsushi Kajimoto TOKYO, Feb 12 (Reuters) - Japan's core machinery orders suffered their steepest fall on record in December, a worrying sign that the manufacturing sector is not doing the heavy lifting required for a durable recovery in the world's third-biggest economy.

The 15.7 percent slump in orders, a leading indicator of capital expenditure, was much worse than a projected 4.1 percent decline and was the largest in comparable data available from fiscal year 2005.

The data could fuel scepticism of Prime Minister Shinzo Abe's reflationary policies, known as "Abenomics", which has combined a massive injection of fiscal and monetary stimulus to pull the economy out of a decades-long slump.

Tokyo has yet to make structural reforms and foster confidence in growth that could convince manufacturers, which have steadily moved offshore to escape a stagnant economy and rising costs, that they should spend more at home instead of abroad.

Last week, Denso Corp, one of the world's leading auto parts makers, raised its capital spending target for the year to end-March to 305 billion yen ($2.98 billion) from 280 billion yen, but said the additional money would be used mainly to boost production capacity overseas.

"We're having particular success expanding sales overseas, while another factor was that one of our customers moved forward a bit the timeframe for their buildup to production, but this was also focused overseas," Denso Executive Director Kenichiro Ito told an earnings briefing.

It underscored the challenges facing Japanese policymakers as a central plan of Abenomics is to spur capital spending to create a virtuous cycle of job creation, higher wages and consumer spending.

The aggressive stimulus has delivered some success, with the economy rebounding over the past year, consumer confidence rising and inflation accelerating to a five-year peak to the half-way point of the Bank of Japan's 2 percent goal.

However, the reluctance of manufacturers to ramp up their capital spending at home threatens to erode the economic gains made in the past year.

"The data confirmed companies remain wary of boosting capital spending," said Takeshi Minami, chief economist at Norinchukin Research Institute in Tokyo.

"Non-manufacturers are turning cautious after leading capital spending last year as consumers rush to buy ahead of a sales tax hike. Now manufacturers hold the key for the outlook of capital spending," he said.