Changing the tax mix by increasing the goods and services tax while reducing personal and corporate tax rates would "undoubtedly" stimulate the economy, says the boss of the nation's largest bank. Calling for action on Australia's big policy challenges, Commonwealth Bank of Australia chief executive Ian Narev said the bank supports the Business Council of Australia's view on tax policy, "which is we need to have a debate where everything is on the table [to] work out a tax policy that is good for the country in the long term".