Mr Colley said SMSFs can invest without limitations in a public unit trust, but when investing in private unit trusts that are not listed on the stock exchange its imperative to take into account related-parties conditions.

“If an SMSF own less than 50 per cent of the units in that unit trust there's no restrictions on the value that they can invest in the unit trust,” he said.

“However, if the combined value of the super fund and other associated parties with the SMSF is 50 per cent or greater than 50 per cent of the total number of units issued by the unit trust, then you need to be careful.

“Where you've got control of the trust by what we call related parties, then you're restricted to the percentage of the superannuation fund that can be invested in that type of trust. That's called an in-house asset.”

Mr Colley said related parties include the superannuation fund, the trustees of the super fund, the members of the fund, and their relatives, and any companies or unit trusts that they control.

He added if any units that are owned in that unit trust by any of those related parties gives control over the unit trust, then the superannuation fund is limited to its in-house asset limit.

“The in-house asset limit is an amount equal to no more than five per cent of the total value of the superannuation fund,” he said.

“So, if you're going to invest in a unit trust it’s best to get some advice to work out whether related parties control the trust.

“If the related parties do control the trust, then the fund is limited to investing no more than five per cent of the total value of its investments in all its in-house assets.

“It's not only this unit trust, but any other investments that they might have in the superannuation fund that's invested in related-party assets, so you really need to be careful.”

He warned the five per cent test is an annual occurrence so there is no room for flexibility after the first compliance test.

“The first time it's tested is before the superannuation fund decides to make the investment in the in-house asset and every year following that,” he said.