General Motors has halted all non-essential spending and travel while it gets a better idea of the potential impact of Japan’s crisis on the company, the automaker has said.

According to the Wall Street Journal, citing a GM spokesman, chairman and CEO Dan Akerson sent a company-wide notice asking to hold off on any expenses that aren’t critical. The note went out via GM’s employee website.

“We’re just assessing the situation day by day,” the spokesman said.

Akerson has said the potential toll of fallout from the tsunami, earthquake and nuclear crisis in Japan remains unknown. He has been working in recent days to prepare for the worst, including a move to shut down a GM factory in Louisiana that builds unpopular small trucks. In shutting the plant, Akerson said, GM is working ensure adequate supplies at all US plants.

GM also was reported last week to have shut production at a truck plant due to a lack of components and media has also noted that the recently launched Chevrolet Volt ‘range extender’ hybrid uses an automatic transmission made in Japan.

GM has been the most vocal of Detroit’s auto makers in voicing concerns about the magnitude of potential supply chain troubles in the wake of Japan’s disaster, the WSJ noted.

Only last Friday, GM said it would stop work at two European factories and was mulling production cuts in Korea amid growing uncertainty over how its plants around the world would be affected by the crisis in Japan.

A shortage of Japanese-built electronic parts forced GM to cancel all three shifts at its giant Figueruelas plant near Zaragoza, Spain, on Monday but a spokesman told just-auto late in the day production would restart at 22:00CET and would be back to normal on Tuesday though with one more shift cancelled this coming Friday. He cited a Japanese supplier as the reason but would not name the company.

Shifts have also been cancelled at Eisenach, Germany on Monday and Tuesday, the company told the WSJ. Both factories build the B-segment Corsa.