Michaelia Cash bought her fourth property on 4 November last year when she acquired the house next door to her home in the prestigious Perth suburb of Floreat.

The Employment Minister settled on the $1.4 million property a month later. But it was only following questions from the media that Cash registered the new property - on 21 January - or eight days later than she should have. Politicians are required to update their register of interests within 35 days of purchase.

Prime Minister Malcolm Turnbull has accepted Cash's apology, explaining she was "mortified" by the error, and emphasised the delay was only a matter of days and that Cash had been away on holidays at the time.

"She is a very hard working and punctilious Minister and she’s had an oversight here and she’s very sorry about it," he said.

But with the upcoming federal budget widely expected to contain policy targeting deteriorating housing affordability in the eastern states, and just ahead of the Western Australian state election, the incident could contribute to the view the government is out of touch with everyday Australians, many of whom are struggling to buy their first home.

Cash's oversight comes on the heels of former senator Sussan Ley's failure to declare a Gold Coast property she bought while on government business, a misdemeanour that eventually cost her her job as health minister.

See also:

Sussan Ley stands aside over trip including Gold Coast property purchase

Key amendments to ABCC bill passed

Housing affordability on governments' agenda