Sony Corp <6758.T> cut output at five more plants and Toyota Motor <7203.T> delayed restarting assembly lines, as the global supply of parts and products began to feel the full impact of Japan's catastrophic earthquake.

Global electronics and autos companies have been hardest hit by the turmoil, but in an illustration of how the ripples are spreading, Rio Tinto , the world's No.2 iron ore miner behind Brazil's Vale , warned the disruptions posed a threat to its expansion plans.

Miners are already facing longer waits for key equipment as companies ramp up exploration, making shutdowns at plants manufacturing heavy earth-moving equipment and electronics more likely to create additional pressures.

I expect the Japanese situation to impact deliveries of Japanese-sourced equipment ... but so far we are OK, Mark Cutifani, chief executive of AngloGold Ashanti , told the Reuters Global Mining and Steel Summit on Tuesday.

More than 10 days after a 9.0 magnitude earthquake and 10-meter tsunami struck the northeast of Japan, manufacturers are struggling to get back up to speed as factories grapple with power cuts, crippled infrastructure and a shortage of parts.

Companies from Apple Inc to General Motors Co and Nokia Oyj are feeling the impact.

Toyota, the world's largest automaker, said all 12 Japanese assembly plants would now remain closed until at least Saturday and it was not sure when they would reopen. Production lost between March 14-26 would be about 140,000 units.

Electronics giant Sony said five more of its plants, mostly in central and southern Japan and producing digital and video cameras, televisions and microphones, were hit by parts shortages and would close or cut output until the end of March.

If the shortage of parts and materials supplied to these plants continues, we will consider necessary measures, including a temporary shift of production overseas, the maker of PlayStation games consoles said in a statement on Tuesday.

A sixth plant north of Tokyo, was set to resume production on Tuesday, but it could be interrupted by rolling blackouts affecting some areas supplied by Tokyo Electric Power (TEPCO) <9501.T>, which operates the stricken Fukushima nuclear plant.

Including two factories only partially restarted last week, 15 of Sony's 25 Japanese plants are currently affected. It has a total of 54 plants worldwide.

TECH CHAIN VULNERABLE

Japan's grip on the global electronics supply chain is causing particular concern. It produces around a fifth of the world's computer chips and exported 7.2 trillion yen ($91.3 billion) worth of electronic parts last year, research from Mirae Asset Securities shows.

There are a huge number of little bits of the high-tech food chain which are done nowhere but in Japan, said Sam Perry, senior investment manager of Pictet Japanese Equity Selection Fund. Nobody else has the quality or the consistency, and in some cases the technology, to do it.

This is now being felt at Hewlett-Packard , which is still assessing the impact on its business.

Vendors face uncertainty at the minute. The crisis in Japan is already impacting component prices and the importance of the Japan for the memory market will be a worry, Tim Coulling, PC analyst at Canalys, said.

Though production has increasingly been outsourced to China, South Korea and other lower-cost markets, there are over 40 factories in Japan producing a significant proportion of the world's PC and smart phone components, Coulling added.

Fujifilm Holdings <4901.T>, the largest producer of triacetyl cellulose film used in making LCD panels, said its main factories are all west of Tokyo and were not directly affected. It has other facilities in northeast Japan, but said any disruptions were unlikely to damage its earnings.

Konica Minolta <4902.T>, the second-largest maker of the LCD film, said its three factories in the Tokyo region had been affected by the rolling power cuts. Company officials declined to specify what these factories produce.

Camera and copier maker Canon Inc <7751.T>, which has suspended all its domestic camera production until at least Thursday, said a lack of gasoline was affecting distribution and stopping staff getting to work in areas such as the island of Kyushu, where train services are minimal.

Nikon <7731.T>, which makes cameras and precision equipment, said it expected to resume production at all its north Japan plants by the end of March, but warned power cuts and shortages of parts could make a return to full production difficult.

Renesas Electronics Corp <6723.T>, the world's No.5 chipmaker, restarted operations on Saturday at a semiconductor plant in Yamagata prefecture, in northwest Japan, a company spokeswoman said on Tuesday -- leaving output suspended at six of the firm's 22 factories in Japan.

RIPPLES SPREAD

Hitachi Construction <6305.T>, Japan's No.2 maker of earthmoving equipment, said five plants in Ibaraki prefecture, north of Tokyo, closed after the quake. Three have partially reopened, but there is no timetable for re-opening the others.

Tsunami damage to the nearest port means Hitachi is shipping some products from Yokohama, near Tokyo.

Carmakers are also struggling to get production lines restarted with Honda Motor Co <7267.T> extending its production suspension until Sunday from Thursday.

A fifth of the company's leading Japan-based suppliers affected by the earthquake have said it will take more than a week to recover, Honda said late on Monday.

In a sign of some return to normality, Japan's top three steelmakers saw some progress in restoring production.

Nippon Steel Corp <5401.T> said output at the three blast furnaces at its mainstay plant in eastern Japan had recovered to pre-quake levels, while JFE Steel Corp <5411.T> said two blast furnaces at its 10 million tons-a-year plant near Tokyo were now operating normally.

(Additional reporting by Junko Fujita and Nathan Layne in Tokyo, James Regan in Perth, Tarmo Virki in Helsinki and Clara Ferreira-Marques in London; Writing by Lincoln Feast and Alexander Smith; Editing by Ian Geoghegan and Jane Merriman)

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