Among Japan’s export markets, North America, Europe and the Middle East, respectively, will feel the greatest pinch if the island nation’s vehicle output faces extended disruption from last week’s killer 9.0 earthquake.

Toyota has said it would halt production through at least today, while Honda extended its shutdown to March 20.

Should the crisis continue through a full 5-day week, the world’s second-largest vehicle-producer would see a shortfall of 209,100 production units, according to Ward’s data.

The lion’s share of Japan’s export-market output, some 1.73 million vehicles annually, goes to North America. Based on recent line rates, one week’s worth of that total would be 37,500 units. Europe sees 936,496 Japanese imports, which translates to 20,300 lost units over five days.

And Middle Eastern markets, led by Saudi Arabia’s tally of 118,132, absorb 583,684 vehicles, or 12,700 per week.

Despite China’s vibrant consumerism, which accounts for 245,325 vehicles per year, Asian markets trail the Middle East on Japan’s export list with 573,306, or 12,500.

Honda can expect to lose 22,400 vehicles before it resumes production, but a complete, week-long shutdown would hit Toyota hardest among Japanese auto makers. The world’s largest auto maker would see 72,000 lost units, followed by Nissan and Suzuki, with lost-unit totals of 25,400 and 24,300, respectively.

Nissan’s plant in Tochigi prefecture is among the assembly sites closest to the quake’s epicenter. Home to the Nissan GTR and 370Z sports cars and Infiniti-brand EX, FX, G and M vehicles, it has suspended output until March 18.

Industry observers in Japan have mixed feelings about the prospects of restarting production. Auto makers were able to resume production one week after 2004’s Niigata Chuetsu quake, which measured 7.0 on the Richter scale.

“Production at domestic plants is also not particularly high at present, so from a medium-term standpoint, we do not expect the stoppage to create major opportunity losses,” says Goldman Sachs Japan analyst Kota Yuzawa.

But Kohei Takahashi at J.P. Morgan Securities Ltd. sees things somewhat differently.

“Given the 20,000-30,000 parts that go into making an automobile, and the difficulty of procuring even basic materials, we do not foresee a return to normal production schedules anytime soon,” Takahashi says.

Adds Yuzawa: “Assuming marginal profits of ¥500,000 per vehicle ($6,122), we estimate the profit impact of stopping production for one day at approximately ¥6 billion ($73.5 million) for Toyota, ¥2 billion ($24.5 million) for Honda, Nissan and Suzuki and less than ¥2 billion for Mazda.”

Impact on Daihatsu and Subaru likely will be about ¥1 billion ($12.2 million), Yuzawa says.

with Roger Schreffler in Tokyo