Shares in Japanese manufacturers tumbled in the aftermath of Friday's devastating earthquake, as companies struggled to gather information from the stricken area and investors worried production could be hobbled for an extended period.

The tremor and tsunami may have killed more than 10,000, while knocking out transport and communication links in parts of northern Japan, where millions are still without water and electricity.

Auto and electronics makers were among the worst hit when trading resumed on Monday, with the sustained strength of the yen helping to push down exporters' shares.

Toyota Motor Co <7203.T> said it would suspend production at all its domestic car plants until at least March 16, reducing output by at least 40,000 vehicles. Shares in the company were down almost 8 percent. Honda <7267.T> said its Japan plants would remain shut to March 20.

Rough calculations indicated the profit impact of stopping production for one day would be about 6 billion yen ($73.3 million)for Toyota and 2 billion yen for Honda and Nissan, Goldman Sachs said in a report.

Another report by Goldman Sachs said there would be extreme damage across the electronics industry supply chain in the near term.

It will take quite some time until investors' confidence in Japanese manufacturers returns. When we look back at the Kobe earthquake, it took about a week to get an overall picture of the magnitude of the damage, said Toshihiko Matsuno, senior strategist at SMBC Friend Securities, referring to the 1995 earthquake that killed more than 6,400 people.

Concerns about rolling power blackouts that will affect Tokyo and surrounding areas over the next few weeks added to the existing challenge of inspecting and repairing north Japan plants amid further aftershocks.

Although northern Japan is relatively sparsely populated and less industrialized than central and western areas, it is an important focus for nuclear power generation.

At this point, it's absolutely unclear how the power cut will affect manufacturers' production and businesses, Matsuno said.

Many firms said they were still trying to compile information about the condition of their plants.


Analysts said investors were likely to be risk-averse, especially given fears over a radiation leak at a nuclear plant north of Tokyo, which was rocked by a second hydrogen explosion on Monday.

Shares in Sony Corp <6758.T> lost 9.1 percent after the company suspended production at eight plants in the affected region and said it was not sure when production would restart.

Nissan <7201.T> shares dropped 9.5 percent, with the automaker shuttering all four of its auto assembly plants in Japan.

Toshiba Corp <6502.T>, a conglomerate whose products include semiconductors and nuclear reactors, dived 16 percent. The company said it did not know when it would be able to re-open its chip factory in northern Japan. Hitachi <6501.T>, a rival nuclear power player, also fell 16 percent.

Shares in Tokyo Electric Power Company (TEPCO) <9501.T> plunged 24 percent.

The potential impact from the situation at TEPCO's nuclear power plant is the biggest difference between this earthquake and the Great Hanshin earthquake, said equities strategist Kiichi Murashima at Citigroup, referring to the Kobe disaster.

There is a chance that a meltdown will occur at the plant in Fukushima. A reduction in power supply would of course severely impact Japan's economic activity, he added.

The nuclear industry would also likely see an effect on long-term sales, he said.

Amid the destruction, there were some winners among Japanese stocks. Construction shares surged on expectations of booming orders to rebuild northeastern Japan, pushing the construction sector index <.ICNST.T> up 6.4 percent. Shares in general contractor Kajima Corp <1812.T> jumped 22 percent, while rival Hazama Corp <1719.T> rose 41 percent and home builder Misawa Homes <1722.T> was up 19 percent.

But a mood of confusion and concern took hold across much of corporate Japan, while transport woes kept many Tokyo workers at home for the day.

We have no idea when we can resume operations at our suspended plants, said a spokesman for Canon Inc <7751.T>. We can't put together plans for tomorrow either, because TEPCO's power outage schedule is uncertain. We are struggling to gather information.

($1 = 81.915 Japanese Yen)

(Additional reporting by Mariko Katsumura and Mayumi Negishi; Editing by Anshuman Daga and Vinu Pilakkott)