Toyota Motor Corp <7203.T> is set to post a drop in quarterly operating profit on Tuesday as supply shortages from the March earthquake kept output low, while floods in Thailand pose a fresh threat for the rest of the year.

Toyota is also struggling to cope with a stubbornly strong yen, which is making its annual exports of 1.5 million vehicles from Japan unprofitable and less competitive against cars from the likes of Hyundai Motor Co <005380.KS>.

Once the world's most envied and profitable automaker, Toyota has also lost its shine against domestic rival Nissan Motor Co <7201.T>. Nissan last week lifted its profit forecasts as it achieves strong sales growth in developed and emerging markets with popular new models.

A Reuters survey of 12 analysts put Toyota's operating profit for July-September period at 101.3 billion yen (810.3 million pounds), down 9 percent from the year-earlier quarter.

The focus will be on how executives account for the uncertainty surrounding the Thai floods, which have forced it to halt work at its three vehicle plants in its Southeast Asian export hub from October 10 at least until November 12. A shortage of parts has also forced it to reduce production in nine other countries including Japan.

Toyota said on Tuesday it would keep its Japanese production reduced at least until November 18. It was still undecided on production elsewhere, including in Thailand.

Between October 10 and November 12, Toyota would lose production of about 150,000 vehicles from the supply shortage, a spokeswoman said. This week, its Japanese factories were working at 70-80 percent of planned levels, while output in the Philippines, Malaysia, Indonesia, Vietnam and Pakistan was at 40 percent of plans.

Its North American factories, excluding Mexico, were working at 90 percent of plans.

The cutbacks have happened just as Toyota was starting to ramp up global production from September, working overtime and some weekends to make up for output lost after the March 11 disasters in Japan.

Many analysts expect Toyota to stick to its forecast for operating profit in the year to next March 31 of 450 billion yen given the uncertainty. Consensus forecasts from a survey of 21 analysts by Thomson Reuters I/B/E/S put the profit at 486 billion yen.

The supply constraints from the two disasters have hit Toyota's sales and market share and will likely place it behind General Motors Co and Volkswagen AG this year. Toyota is still by far the most valuable, with a market capitalisation of $113 billion.

Toyota must also find a way to keep its commitment to build at least 3 million vehicles annually in the shrinking Japanese market without bleeding profits. It has said it needs the dollar to be at least at 85 yen to break even in Japan. The dollar was trading around 78 yen on Tuesday.

Toyota's shares have fallen 21 percent in the year to date, faring worse than Nissan but better than Honda Motor Co <7267.T>, which are down 4.9 percent and 25 percent, respectively.

(Editing by Matt Driskill and Michael Watson)