Rainmaker's head of research Alex Dunnin said it is important to note that cash allocations are not indicative of the total amount of cash held by the fund."It’s a curious thing for them to do but it’s something they have been doing for quite a few years,"Mr Dunnin said of the zero per cent cash allocations.

Unisuper said its balanced option had 30 per cent allocated to defensive assets but this was in bonds,not cash.

Hostplus has paid out more than $1.05billion to members tapping into their super early and now reports regularly to members on the liquidity of the fund. Earlier this month Hostplus reported it had $4.6 billion in cash,representing 10.2 per cent of the total fund.

The APRA data showed super contributions rose 6.9 per cent to $121.1 billion compared to the same quarter in the previous year and Mr Dunnin said funds would prioritise holding onto these inflows rather than increasing reserves by selling stocks or other assets.

Director of research at Holon Global Investments,Tim Davies,said funds with higher exposure to unlisted assets were most at risk of liquidity concerns over the next two quarters as Australians are able to access another $10,000 from their super. The APRA figures show MTAA's MySuper fund had the highest exposure to infrastructure,followed by AustralianSuper,PrimeSuper and Hostplus.

"The water is warm,it doesn’t take much for it to get hot and this unlisted issue becomes a big issue. Some super funds might have to entertain ideas around forced asset sales,"Mr Davies said.