Treasurer Scott Morrison has accused the big banks of having a "whinge" over the government's new levy, but sought to reassure them he has no plans to lift the impost further.

Continuing his budget sales job at the weekend, Mr Morrison ramped up pressure on the banks not to pass the 0.06 per cent levy - which will raise an estimated $6.2 billion - on to customers.

Treasurer Scott Morrison announced plans for a "one stop shop" for consumer complaints. Credit:Alex Ellinghausen

"If they do, they will say to every banking customer in Australia you are right about the big banks. You are absolutely right about them. That's why they shouldn't do it," Mr Morrison told the ABC on Sunday.

"If banks think the way to build shareholder value is to fleece their customers then I don't think that is a very sound business strategy."