The number of BMW Minis sold dipped ten per cent last month as the German carmaker counted the cost of its £100 million Oxford factory overhaul.

But despite the reverse, BMW said the investment - to increase capacity from 200,000 vehicles to 240,000 a year - would pay off.

Production at the plant had to be interrupted between mid-December and mid-January because of the building works which will be completed in time for 2007.

Bottlenecks and a resultant decline in deliveries led to 12,214 fewer Minis being delivered in February, while in the year to date 9.2 per cent less vehicles (27,754) left dealerships.

A spokeswoman for Mini said: "We are seeing the results of the three-week shut-down as work is carried out improving the facilities at Oxford.

"That has taken a chunk out of production, which has affected our sales in the short term.

"We are not unduly concerned and there is no panic; it is all part of the plan to increase production levels in the medium term. There is still massive demand for Minis out there. Speaking to our dealers there is still a lot of interest."

Overall sales within BMW group increased by 13.8 per cent in February to 94,751, driven by strong performances from its 3-Series.

For the BMW brand, the number of vehicles delivered to customers rose by 18.5 per cent to 82,507 from 69,648, while in the year, 160,763 BMW auto-mobiles were delivered, a rise of 19.5 per cent.

The company said it was particularly pleased with the BMW 5 Series and the BMW 7 Series, which "developed at a particularly pleasing rate" in the first two months.

Sales of the revamped BMW 3-Series surged 53.5 per cent in January and February to 69,232 units, including 46,903 of the saloon version rolled out in early March 2005.

Sales of the estate version - launched last September - gained 69.1 per cent to 15,622 cars.

The BMW 5 Series also recorded a clear increase, with sales rising by 13 per cent in the first two months of 2006 to 33,693

The top BMW model, the 7-Series, recorded an increase of 33.2 per cent to 6,798 units delivered for the period to the end of February.

Sales of the Rolls-Royce Phantom last month dropped from 40 to 30, while in the year to February, it delivered 60 Phantoms, down from 72 last year.

The Munich-based company has been breaking one sales record after another and has overtaken arch rival Daimler-Chrysler's Mercedes.

Dr Michael Ganal, member of the board of management of BMW responsible for sales and marketing, said: "In 2005, we were the world's most successful supplier of premium automobiles, and in the first two months of 2006, we have further increased our lead over our competitors.

"This is a good basis from which to defend our leadership position this year."

Chief executive Helmut Panke said in January that the group aimed to post another record in deliveries this year.

In 2005, BMW group vehicle sales increased 9.9 per cent to nearly 1.33 million units.

Mercedes Car Group reported on Monday that unit sales swelled 16 per cent in February to 83,800 vehicles.

Mercedes-Benz sales gained 23.1 per cent to 76,100 units, while sales at loss-making Smart fell 25.9 per cent to 7,700 cars.