CBA offered up to $2,000, which was relatively modest compared to other deals.

NAB-owned ubank also scrapped its cashback deal in April.

Other banks offered upwards of $4,000 for refinances in a bid to grab market share.

A number of offers are still in the market, including ANZ's which offers up to $4,000 cashback, all the way up to Reduce Home Loans, which offers up to $10,000 on mortgages $2 million or more.

Speaking to the Savings Tip Jar Podcast, Brodie Haupt - CEO and co-founder of non-bank lender WLTH - said cashback offers distorted the mortgage market.

"What we see is is the the major banks failing to understand the cost of acquisition for a customer, and have become quite lazy," Mr Haupt said.

"Rather than trying to invest in education to their borrowers and customers, they've got to look for retention, rather than innovating.

"[Banks] don't want to lose customers and they know that their cost of customer acquisition is higher."