"Overall, the market in western Europe will contract by around 5.0 percent this year and remains a huge challenge for carmakers," BMW chief Norbert Reithofer told the financial daily Börsen-Zeitung.
Furthermore, the situation could last until the middle of next year, he warned.
"Maybe we'll see a slight pick-up in the market during the second half of 2014," Reithofer said.
In the case of BMW itself, the chief executive forecast that the group's share of business in Europe would fall from about 47 percent at present to 40 percent in the coming years.
China, North America and the rest of the world would then each account for around 20 percent of sales.