BMW has said it has not manipulated emissions tests following damaging claims made in a German magazine about the emission levels of one of its diesel models.

Auto Bild reported that the BMW X3 xDrive 20d model exceeds Euro 6 emission limits 'more than 11-fold' in road tests carried out by the International Council on Clean Transportation (ICCT).

"There is no difference in the treatment of exhaust emissions whether they are on (test) rollers or on the road," BMW the German luxury-car maker said on Thursday.

German trade magazine Auto Bild said that BMW's X3 xDrive 20d model exceeded "Euro 6" emissions limits more than 11-fold in road tests by the International Council on Clean Transportation (ICCT).

"No specific details of the test have yet been provided and therefore we cannot explain these results," BMW told Reuters. "We will contact the ICCT and ask for clarification of the test they carried out."