The ATO is set to crackdown on investment property owners, with claims 90% of landlords are filling in their tax returns incorrectly.

About 1.7 million Australians own investment properties and the ATO says because of the errors it is missing out on about $1.3 billion in tax revenue.

It is working with lenders and financial institutions to access personal financial data to help corroborate property use, income and expenses.

Banks are being asked by the ATO to provide bank account details, information about investment properties, how much rent is received and expenses.

It is also monitoring property managers to correct figures are being provided.

An ATO spokesperson says the aim is to help taxpayers get their tax return right in the first place as well as target people who are under reporting income or overclaiming expenses.

The ATO is concerned that some owners are using investment loans for private purposes, such as buying a car or paying school fees.