Just how powerful is Bunnings, the hardware giant and weekend obsession of millions of Australians? That is the question being fought out in a parliamentary inquiry into the country’s big-box retail sector.

Plant growers’ lobby group Greenlife Industry Australia (GIA) asserts that the Wesfarmers-owned retailer controls 70 per cent of all live plant sales, a huge market share it says gives Bunnings the power to dictate terms to suppliers.