The UK has confirmed it is extending the Irish Sea border grace period for parcels.
The British government has defended its unilateral decision to continue the post-Brexit measures until October as the minimum step necessary.
The first of the light-touch regulation schemes on goods from the rest of the UK transiting to Northern Ireland was due to expire at the end of March.
Supermarkets would have had to produce export health certificates for all shipments of animal products since Northern Ireland is part of the EU’s single market.
On Thursday, an HMRC statement said: “HMRC has adopted a temporary approach to applying declaration requirements for the movement of goods in parcels (including by the Royal Mail Group and express carriers).
“The temporary approach recognises the unique circumstances of Northern Ireland, the impacts of any disruption to parcel movements in the context of the coronavirus (Covid-19) pandemic, and specific challenges for operators moving parcels.
“This guidance sets out the detail of this approach.
“In almost all cases, goods sent to consumers will not require a customs declaration.”
Declarations will only usually be required where the goods are either prohibited or restricted or being sent from a business to another business where the value of the goods is greater than £135.
HMRC added: “For business to business movements, these temporary arrangements will end on 1 October.
“We will publish further guidance setting out longer term requirements in due course.”
Businesses in Northern Ireland have been pressing for an extension to the grace periods to avoid a cliff-edge plunge into extra bureaucracy linked to the Northern Ireland Protocol.
European Commission vice-president Maros Sefcovic has said the UK is in violation of its post-Brexit obligations.
Britain is set to breach international law for a second time, he has warned.
The Irish Government also branded the intervention extending the soft-touch regulatory regime on some goods entering Northern Ireland from Great Britain as “deeply unhelpful”.
The protocol is designed to prevent the imposition of a hard border on the island of Ireland by keeping Northern Ireland following EU trade rules.
It has caused disruption to some goods after suppliers encountered extra red tape.
Ministers have faced a backlash from unionists who fear the protocol threatens Northern Ireland’s place in the UK internal market.
Minister for Foreign Affairs Simon Coveney has said: “A unilateral announcement is deeply unhelpful to building the relationship of trust and partnership that is central to the implementation of the protocol.”