An oversight by the Australian Bureau of Statistics (ABS) has led to a same-sex marriage survey being sent out with the word "bumsex" printed in a barcode.

More than 16 million surveys were sent out across Australia by the ABS, allowing people to have their say in the postal plebiscite on same-sex marriage.

Each survey features its own unique computer generated barcode. Some of the letters beneath these barcodes have inadvetantly spelled rude wods - including "bumsex".