A so-called Tesco tax on large retailers is introduced in Northern Ireland this weekend.
The levy to subsidise rates relief for small businesses has been criticised by Sainsbury's chief executive Justin King, among others, amid arguments that it unfairly targets the supermarket sector and could limit investment and cost jobs.
Stormont Finance Minister Sammy Wilson has said it represents a minuscule proportion of the giant retailers' profits.
The charge will affect 76 large shops and raise £5 million to fund a rates cut for small shops.
The levy will be at a rate of 15 per cent, not 20 per cent as originally planned.
The tax is introduced on April 1.