Mr Whittaker would not comment on whether he saw a link.
Havelock North New World, Hastings New World and Hastings Pak'nSave now stock Christchurch mushrooms.
In a letter to the editor today, the CEO of the Hawke's Bay Chamber of Commerce, Wayne Walford, said he was very disappointed at the stance taken by Hastings supermarkets to buy produce from Christchurch when other Foodstuffs group members "buy our local produce".
Ms McDade said the inaugural Growers' Market received positive feedback from the 20 stallholders, CBD retailers and shoppers.
It was planned to open on two blocks of Heretaunga St East but instead opened on one block because of a lack of vendors, including Farmers' Market stallholders worried it would undermine their Sunday market at the showgrounds.
Ms McDade said Saturday would see more vendors "now they [Foodstuffs] have publicly said they are not blocking anyone from coming".