ANZ has tightened lending restrictions in 11 postcodes in Perth and Brisbane to ensure borrowers are being honest in their applications and amid concerns about oversupply of apartments.

The big-four bank sent its mortgage brokers a list of 25 suburbs in which borrowing will be capped at 80 per cent of the apartment's value.

The tighter rules apply to resdiential apartments, including off-the-plan apartments and apartments worth less than $3 million.

Related content: Citi clamps down on lending in 'blackspot' suburbs

ANZ has also issued brokers with a docment that outlines the "minimum requirements and guiding principals" required in the broker-client transaction, reminding them that loan applications must only contain truthful information.

UBS recently issued a report claiming that up to one third of all Australian home loans could be 'liar loans', or loans issued on the basis of untrue information.

Brokers will be required to document elements of their conversations with clients, and must show the client's complete information and reasoning for the loan recommendation.

Brisbane

4000 Brisbane CBD, Spring Hill, Petrie Terrace

4006 Fortitude Valley, Bowen Hills, Herston, Newstead

4010 Albion

4011 Clayfield, Hendra

4014 Banyo, Nudgee, Virginia

4102 Dutton Park, Woolloongabba

4171 Hawthorne, Bulimba, Balmoral

Perth

6000 Perth CBD

6004 East Perth

6104 Redcliffe, Ascot, Belmont

6151 Kensington, South Perth

Data shows apartment prices are falling

According to data from the REIWA, the Perth median apartment price as of 30 June 2017 was $407,000, that's down 3.1 per cent from $420,000 the previous quarter, but down just 0.7 per cent from $410,000 compared with the same time the previous year.

Perth's median apartment prices are down 10.0 per cent from their high of $452,000 in June 2014, according to the REIWA data.

CoreLogic data shows that Brisbane's median apartment price as of the end of August, was $386,412, down 3.2 per cent for the year, and down 0.8 per cent for the quarter.

Read more about lending restrictions in the Australian mortgage market:

Citi clamps down on lending in 'blackspot' suburbs

One third of all home loans based on "lies": UBS

APRA tightens bank rules to restrict risky lending