Deputy Prime Minister Barnaby Joyce says he is open to hearing from Coalition MPs about a push to create a tribunal to help victims of so-called "bank bastardry", amid growing calls for a royal commission.

Queensland Liberal Warren Entsch and Nationals senator John "Wacka" Williams have called for a new tribunal to be created to consider practices within the banking industry, with a focus on customers and possible penalties for corporations who have predatory practices.

Rulings from the tribunal would be binding.

Labor believes it has the numbers to push for a banking inquiry in the Senate, while Opposition Leader Bill Shorten wrote to Prime Minister Malcolm Turnbull again this week asking to reconsider his opposition to a royal commission.