More than 15.5 million Australians have not made a binding death benefit nomination for their superannuation, leaving funds free to decide who inherits their money when they die, according to research from Super Consumers Australia published Monday.

A survey of 5,000 people found 67 per cent had not been contacted by their fund about making a binding nomination in the past 12 months, while only 10 per cent had. The finding comes after Brooke Allan's uncle's non-binding nomination was overruled by his super fund, Cbus, which awarded his $130,000 payout to his estranged son instead of the nieces he had named.

Under Australian law, superannuation does not automatically form part of a person's estate or pass according to their will. As trustee, the super fund has discretion to decide beneficiaries. The federal government is consulting on whether to introduce mandatory time frames for funds to respond to claims, Nassim Khadem reports for ABC business (AU).