ANZ said, in a statement, that the changes reflected “the increasingly complex financial environment and the continued softening of the property market”.

“Other factors are also coming into play, including reduced consumer spending and rising unemployment.”

The banks said that while there was no “standard scenario”, generally speaking they would not be offering new lending on transactions where the loan to property value ratio (LVR) exceeded 80%.

“In some specific circumstances we may be in a position to lend above 80% but customers will be required to demonstrate an undoubted ability to service the loan in the event of changed financial circumstances.

A new registered valuation will be required for loans above 80% LVR.

Lo Doc applications will be considered up to a maximum of 60% LVR.

“We will continue to support our residential investment customers but are unlikely to lend above 80% LVR. For all new residential investment lending applications, we will seek a registered valuation where the LVR is greater than 75%.

Not all lenders have put out formal announcements about changes to lending policies as the credit crunch has taken hold but brokers report that mortgage applications are subject to increased levels of scrutiny.

Sovereign has announced a number of changes to its criteria in recent months and lending industry sources say that ASB appears also to have tightened significantly.

The changes had included restricting lending – as in the case of ANZ and The National Bank - to loans with LVRs of less than 80%, which, at the time introduced were tougher than other banks.

ASB head of retail banking, Ian Park, said that bank had reviewed lending criteria several times over the past six to nine months, anticipating changes in the economic environment that were now materialising.