The Revenue Minister says he wants to get the facts out about tax, so politicians and voters can have a more informed debate about tax rules.
David Parker's proposed bill would require periodic reporting about how the tax system is faring.
He claims there's no way of knowing what rate of tax is paid by the very wealthy, at present.
Parker says surveying people about tax has proven to be ineffective.
But Inland Revenue is now collating new tax data.
He told Morning Report if it's found the wealthy aren't paying their fair share of tax, then there should be political debate about what to do.
