Registrations of new cars in February were down 22% against the same month in 2008.
The slowdown continued across all sales types, fuel types and segments, with the notable exception of the mini sector.
New models in the mini segment have helped achieve a 47.3% rise in February and a 42.7% gain over the first two months of 2009.
“New car registrations continue to decline and although government recognises the strategic importance of the UK motor industry, urgent action is still needed,” said Paul Everitt, SMMT chief executive.
“Other European countries have been proactive in assisting their automotive industries and it is imperative that UK government increases the pace in responding to industry proposals for a scrappage scheme and access to finance and credit.”
Sue Robinson, director of the RMI National Franchised Dealers Association, said: "Consumer car buying patterns continue to be affected by the current economic situation."
"While new car sales in February were still well below the numbers seen in 2008, according to our car dealer members, used car sales in February 2009 were still extremely robust."