Mark Matthews did not raise the rent on his three-bedroom investment property in April, but kept the Christies Beach rental house at $410 a week.

Matthews, a business consultant, raised the rent on his long-term tenant by $100 last year – the first time since 2015 that the rent of his southern suburbs Adelaide home went up – but decided not to increase it this year, even though he says the current rent is $100 below his suburb’s average.