Honda’s new Insight hybrid vehicle has been on sale in the U.S. for just over a week but demand for the car is already pushing production at the company’s Suzuka plant in Japan to the limits. Sales of the Insight in Japan are already triple what Honda had hoped for and with predictions of up to 100,000 sales in the U.S. alone, Honda will have no choice but to increase production.

Unfortunately, Honda can only build about 600 Insights per day and half of these are already destined for the U.S. Moving production to North America now sounds like a good idea but executives at Honda say such a move is still a long way off.

The turbulent U.S. car market has already seen Toyota delay plans to build its Prius locally, and whether or not demand for the Insight is maintained remains to be seen. There’s also the issue of a lack of suitable suppliers as most of the Insight’s low-cost hybrid components are sourced exclusively from Japan. Then there are concerns about finding the right workers.

Speaking with Automotive News, Honda plant manager Hidetomo Mori said the company needs to develop its human resources outside of Japan before even thinking about building the Insight in other markets.

In the meantime, Honda will work on improving its manufacturing process so that capacity can be lifted to 250,000 vehicles per year from the current 200,000 limit. But the carmaker has a major threat on the horizon. Toyota plans to sell a low-cost version of its second-generation Prius alongside the new 2010 model in Japan to compete directly with the Insight, and there’s a strong chance that the same could occur in other markets.