Australians face hidden taxes on their superannuation despite the Federal Government promising capital gains tax changes would not affect retirement savings — leading to yet another potential Budget backdown.

Shadow treasurer Tim Wilson has seized on a discovery by the Financial Services Council that Australians with $372 billion in super assets face an additional $55 million a year tax bill if their superannuation is held in a managed investment trust or an attribution managed investment trust.

“The Albanese Government has been caught laying yet another tax landmine in its Budget to feed its spending addiction, and this time it’s targeting superannuation,” he said.

Mr Wilson accused Labor of targeting retail super funds while being gentler to union-backed industry super funds.

“Labor thinks super is their money, and they’ll rig the rules to ensure Australians’ super goes into the funds their mates control, and tax anyone who wants to control their own retirement,” he said.

A May Budget explainer from Treasury promised that super, including self-managed superannuation funds, would be exempt from Labor’s capital gains tax changes.

“These changes will apply to individuals, partnerships, companies and most trusts. Widely held trusts (for example, most managed investment trusts) and superannuation funds (including SMSFs) will be excluded,” it said.

But a new analysis from the Financial Services Council, which represents retail superannuation funds, revealed $372b worth of super assets were potentially affected.

Australia’s $4.4 trillion superannuation sector also includes $2.6 trillion worth of profit-driven super and self-managed super funds.

Financial Services Council chief executive Blake Briggs is calling on the Government to amend its capital gains tax changes announced in the Budget so managed investment trusts and attributed managed investment trusts were taxed the same way.

“We have had constructive discussions with Government and Treasury, and we are optimistic there is a genuine willingness to work with industry to fix this issue,” he said.

“The last thing anyone wants is for Australians’ retirement savings to be worse off because of technicalities that were never intended.

“On Budget night, the Government explicitly stated that superannuation funds would be unaffected by the changes.”

FSC modelling showed super held in a managed investment trust or an attribution investment trust would incur a 16 per cent higher tax bill compared with retirement savings held directly.

An amendment to fix how capital gains tax is applied to super would mark the third major backdown since the Budget, to avoid unintended consequences.

This would follow a scrapped plan to impose a 30 per cent tax on discretionary testamentary trusts, used for estate planning purposes, and the widow’s tax that stopped grandfather provisions on negative gearing for investment properties being transferred to a spouse in the event of a death or a divorce.