New data from Australian Property Monitors has identified Australian suburbs where it is now cheaper to buy than rent.

APM found 91 suburbs where a mortgage on the house was a cheaper option than renting and 123 suburbs where buying a unit was cheaper.

Four Illawarra suburbs featured on each list.

The figures are calculated using yearly median house prices to the end of April 2009, median rents and weekly payments on an interest-only mortgage at the present variable rate of 5.8 per cent.

Cringila ranked 21st on the national list, where home buyers potentially saved $28.63 a week by buying a house rather than renting.

When it came to units, West Wollongong ranked seventh Australia-wide.

Macquarie Capital Advisers property strategist Rod Cornish told Domain.com this stage of the property cycle could be fleeting as first home buyers moved rapidly, but rarely was the "rent-buy equation" as broad as it was now.

"The last time there were so many suburbs where you could buy cheaper than you could rent was back in 1987," Mr Cornish said.

Illawarra Real Estate Institute chair Leigh Stewart said a lot depended on interest rates, but the figures emphasised how good a market it was at the moment.

Mr Stewart said figures for some of the Wollongong suburbs named were influenced by the university's growth.

"An 8 per cent increase in student numbers this year is adding to the serious housing shortage that doesn't look like it will decrease," Mr Stewart said.

According to APM, Cringila's median house price had fallen 13 per cent in the year to May, but Pam Webster of O'Connor First National said after a slow end to 2008 buyers were now moving quickly.

This week Ms Webster sold 5 Monteith St for $219,000, the 15th Cringila property to sell for less than $250,000 in the past six months.

"Cringila is easy to get to with buses and railway ... it is a convenient place."