Retailers have been warned that they must stay closed until 1pm on Anzac Day.
The Department of Labour said the Shop Trading Hours Act Repeal Act 1990 specified three-and-a-half days on which most shops must close -- Christmas Day, Good Friday, Easter Sunday, and until 1pm on Anzac Day.
"If a business does not fall into one of the exempted categories under the Act - or is not in an area that has an exemption issued by the former Shop Trading Hours Commission - it is an offence to open and trade during any time the law restricts trading," the department said today.
"The owner or occupier of such a shop may be prosecuted and fined."
Retailers can contact the department for information on how the laws apply to their business.
The department said it intended to take action against a number of retailers found to be open on Good Friday when they should not have been. Most were garden centres, although there were also three music stores.
On Easter Sunday, more retailers were found to be trading in Auckland, Hamilton, Tauranga, Hawke's Bay, Wellington and in Christchurch and will face action.
