The nation’s largest superannuation funds were repeatedly warned they were underprepared for cyber threats before criminals hacked into thousands of accounts and stole retirees’ savings in a co-ordinated attack early on Friday.

Accounts managed by industry funds AustralianSuper, Australian Retirement Trust, Hostplus and REST were broken into. Insignia, the ASX-listed firm that owns the MLC Expand platform, said hackers had breached its systems in the same attack.