Sales of BMW brand vehicles rose 7.4 percent to while Mini brand volumes edged 0.2 percent lower, according to data published by the company on Tuesday.

"Following on from the best first quarter in the company's history, we have just reported our most successful April sales ever," said Ian Robertson, head of sales and marketing for the BMW brand, in a statement.

"We are well on course to achieving a record year in 2012," he added.

By comparison, sales growth at Daimler's luxury car brand Mercedes-Benz dropped off its double-digit monthly pace, slowing in April to its lowest rate with just 3.6 percent more cars sold over the previous year's month, according to Reuters.

Much of that was due to an 11 percent decline in volumes in China, which Mercedes blamed on limited product availability due to model changeovers.

Last week, BMW reported first-quarter profits that hit a new record high and surpassed even the most bullish analyst estimates thanks in large part to China, now it's single biggest market. It also forecast April volumes would rise about 6 percent.

A rising class of affluent Chinese eagerly snap up luxury brands and have a particular affinity for German luxury cars, which amassed an 80 percent share of the premium market. Virtually every second 7 Series limousine, BMW's top-of-the-line flagship, is sold in China.