It was the best September performance since the introduction of the twice-yearly release of new registration plates in 2001.
The percentage of private new car sales financed by FLA members in the 12 months to September 2014 increased to 75.8 per cent, a record high.
The consumer used car finance market also saw growth in September, with volumes and values up by 15 per cent and 23 per cent respectively, compared with the same month last year.
Paul Harrison, head of motor finance at the FLA, said: ‘Over £3.2 billion was provided by FLA members to help businesses and households fund car purchases in September.
‘Motor finance is a very competitive market, driven by savvy consumers shopping around to compare deals before visiting their local dealership. Competition keeps prices keen and customer service high.’