MORE Australians are falling behind on their home loans, despite the mining boom, according to a report released yesterday by the ratings agency Moody's.

The 6168 postcode taking in Rockingham, 30 kilometres south of Perth, has the highest delinquency rate in the country with 5.31 per cent of mortgages more than 30 days overdue - more than three times the national average of 1.67 per cent.

Falling behind ... NSW is the worst-performing state when it comes to defaults on mortgage payments, especially around Sydney. Credit:Tamara Voninski

But NSW retained its title as worst performing state, with six of its 21 regions, concentrated on Sydney, turning in very poor performances.

A Moody's senior analyst, Arthur Karabatsos, said the two biggest declines in mortgage performance were in mining boom states Western Australia and Queensland.