Minimum balances should have been applied to self-managed superannuation funds (SMSFs), according to former Cooper review panel member Sandy Grant.

"The Cooper panel had made only some recommendations for the SMSF sector ... I would have established a minimum balance for SMSFs," Grant told an audience at a Deloitte breakfast in Sydney on Friday.

Grant said about 25 per cent of people who had SMSF balances of less than $50,000 had not contributed to their fund for two years.

"Obviously some people are making a lot of money from establishing these funds," Grant said.

A minimum balance for SMSFs would have been a barrier to the industry, according to Self-Managed Super Fund Professionals' Association of Australia chief executive Andrea Slattery.

"The reason why the Cooper review did not recommend a minimum balance on SMSFs is because the sector has outperformed all other sectors and has lower fees than even the industry funds," Slattery said.

"Statistics prove that there is 100 per cent engagement by members. These funds also adequately address adequacy and longevity risk issues," she said.

Slattery said contributions do not necessarily have to be regular as people have the option when to contribute to their SMSF.

"One year they may want to just contribute their SG [superannuation guarantee] into the fund or another year they may want to make voluntary contributions. Other times they may make no contributions," she said. 

"That's the beauty of SMSFs. You can contribute to the fund at your leisure."