The same lending policies for individuals also apply to SMSF lending. An SMSF also needs to service the potential debt at an assessment rate, but the SMSF's income sources are a bit different from that of an individual.
There's already significant restrictions on LVR for SMSF lending. Rates are already higher.
I did see one proposal that SMSF should only be able to lend against established property (not brand new). Whilst I don't agree with this, it would shut down a lot of property sprukers overnight.