The ANZ-National, Westpac, BNZ and ASB are all Australian-owned banks trading in New Zealand.
Those four made more than $14 billion profit in New Zealand between 2008 and 2011, and that's caused the Green Party to call for the Government to inject some money into Kiwi-owned banks so they can be more competitive.
But the bankers association has come back saying there's already a good deal of competition, and even as they're making profits the banks are paying taxes here.
Campbell Live decided to get the caravan out to find out what you think.
Are they greedily taking profit out of New Zealand, or are they offering competitive rates and service in a free market?
Watch the video.