More Australian home-buyers are submitting false information in order to obtain mortgages despite banks and brokers promising tougher lending checks in the wake of the banking royal commission, a new survey by investment bank UBS has found.

The introduction of stronger responsible lending practices – including asking more questions of borrowers and seeking more documentation to support their claims – appear to have failed to reduce the threat to the banking system and economy posed by so-called "liar loans", according to the survey, which pointed to a record-high number of borrowers admitting their applications were "not completely factual".

More than a third of Australian home loans could be 'liar loans' based on inaccurate information. Credit:Rob Homer

Analysts from UBS conducted detailed surveys of 903 people who had taken out a mortgage in the past financial year, finding more than a third of them – 37 per cent – had not provided accurate information to their financial institution, up from 32 per cent the year before. It has been estimated previously that as much as $500 billion of home loans may be underpinned by fake customer information.

"While asking detailed questions appears to be prudent, it does not appear to be effective as many factually inaccurate mortgages are still working their way through the process," analyst Jonathan Mott said.