In a note received by mortgage brokers last week, NAB listed more than 80 "restricted postcodes" across the country where it is capping the percentage of a property's purchase price it will lend, known as a loan-to-valuation ratio. Within this group, NAB identified 40 highest-risk postcodes, which were dominated by mining areas in WA and Queensland. Known as "Group A restricted postcodes" these are "areas where significant deterioration in credit risk has been observed", the bank said. In these areas, NAB said it had introduced a cap of 70 per cent on loan-to-valuation ratios for new lending - meaning new borrowers will need a deposit of at least 30 per cent. NAB also included a second group of "Group B" postcodes where it is eyeing future risks and capping LVRs for new lending at 80 per cent.

The second group of postcodes takes in "areas which are exhibiting characteristics which may indicate future deterioration in credit risk," the bank said. Sydney highest risk This "B" group was dominated by Sydney suburbs, which accounted for 34 of the 43 postcodes listed in this category. It included a range of suburbs from across city, ranging from inner-city areas such as Glebe and Chippendale, to Campsie, Kingsgrove, Chatswood, Baulkham Hills and Cabramatta.

Five Melbourne suburbs were also included on the list of "Group B" areas, including the Melbourne CBD, St Kilda Road Central and Abbotsford. NAB will also cap LVRs at 80 per cent in central business districts of Adelaide, Perth and Brisbane, the note says. "We continually review our risk settings to ensure we're lending responsibly and sustainably. This is a very normal practice for any bank," a NAB spokeswoman said. "We recognise that in any property market, no two suburbs are the same and these strategies take into account a range of economic factors and provide an extra level of caution to our risk settings." Suburban surprise

While banks commonly take a more cautious approach to mining and one-industry towns, brokers say it is unusual for a bank to adopt such a cautious approach towards suburbs in Sydney. It comes after NAB chief risk officer last month David Gall said the bank had developed a list of 40 hostpots, but it did not identify the areas. NAB said the postcode policy would apply to all new loan applications received that had been received after September 18. The managing director of mortgage broker Homeloanexperts.com.au, Otto Dargan, said the policy may affect first home buyers especially, as they typically had smaller deposits. With Sydney dwelling prices up 17.6 per cent in the last year, Mr Dargan also questioned whether the policy was a vote of no confidence in parts of Sydney.

"It could be NAB did this for internal reasons, such as being overexposed in those suburbs. Or it could be vote of no confidence in large parts of the Sydney property market," he said. More economic news and analysis

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