AUSTRALIANS are saying "I don't" when it comes to religious weddings.

The percentage of couples married by a religious minister dipped to under a third last year, down from almost 60 per cent 20 years ago.

According to the latest figures from the Australian Bureau of Statistics, released on November 30, seven in 10 couples (69.2 per cent) who married last year were wed by a civil celebrant - a 27.1 percentage point increase from 1990.

At the same time, the number of couples who tied the knot in a religious ceremony dropped from 57.9 per cent in 1990 to 30.7 per cent last year - and 16.5 percentage points in the past decade alone.

Sydney civil celebrant Sue Sherratt said she was receiving more requests for her services than ever before.

Ms Sherratt was booked out for every weekend between September and December this year and has had to turn down requests to wed couples in March due to bookings.

She is already taking requests for dates in November next year.