BMW expects to increase the number of Mini hatchbacks it builds at its plant in Oxford, England by around 10% over the next few years, Reuters reported.

According to Reuters, BMW chief executive Helmut Panke told analysts in a conference call the production ramp-up will be done gradually.

"We are not looking at another facility to build Minis. Oxford is its home, and we have some good ideas to increase volume production there step by step... 180,000 a year would not be out of this world," Panke said, according to Reuters.

Reuters said the Mini’s success has taken BMW executives by surprise and kept the firm's sales growth on the rise as its core BMW brand cars reach a low point in their product cycle.

The company built around 160,000 Minis in Oxford last year with the factory running at its current full capacity and sold over 144,000, with the United Kingdom and the United States its top two markets, Reuters said.

According to the news agency, investors initially worried that BMW would struggle to make much profit on a product pitched squarely at the lower-margin small car market, but the company says it now makes money on every Mini it sells.

According to Reuters, chief financial officer Stefan Krause said the extent of demand for the more expensive and faster Cooper and Cooper S versions had surprised the company. They had initially expected the basic Mini One model to account for 60 to 70% of sales.

"It is exactly the opposite now. Sixty to 70 percent is what the Cooper and Cooper S models are contributing, and these are very high-margin vehicles," Krause reportedly said on the call, according to Reutersm adding the company was selling more optional extras on the cars than expected.

BMW is expected to launch a Mini convertible in the near future and also introduced a diesel version of the car at the Geneva motor show earlier this month, Reuters said.