Two out of three types of checks on items arriving here from Great Britain from January 1 are to be carried out before departure on the other side of the Irish Sea, it has emerged.
As Northern Ireland will be treated as remaining in the EU's single market for goods at the end of the Brexit transition period in just eight days, it will have to comply with EU rules on food, plant and animal health.
That means checks on goods, animals and even pets coming into here under the NI Protocol, drawn up to avoid a hard border on the island of Ireland after Brexit.
The Department of Agriculture, Environment and Rural Affairs (DAERA) has published guidance on moving goods to Northern Ireland.
They are also providing advice to traders such as supermarkets who will be permitted to move food supplies into here without providing export health certificates over a three month grace period. There is a six-month grace period for chilled meats.
And pet owners bringing their animal companions into Northern Ireland from Great Britain will have a month's grace to adjust to new rules from the end of the Brexit transition period.
The rules will mean ensuring pets have an up-to-date rabies vaccine, an animal health certificate, microchip and a valid tapeworm treatment.
But chief veterinary officer Dr Robert Huey said he hoped that the UK and EU would ultimately be able to agree to arrangements for the free movement of pets around the UK. Physical checks will take place on some goods brought into Northern Ireland on the 16 ferries which travel here from Great Britain every day.
DAERA is responsible for the checks, which Dr Huey said would be carried out on around 40 lorries.
Dr Huey said he and his staff were now ready for the changes, though they had only been able to build temporary structures at ports here for the process of carrying out inspections.
He said documentary and identity checks would be carried out in Great Britain before lorry drivers set sail.
A document detailing the goods will be processed electronically, while they will be identified by a seal which will be applied at the port in Great Britain. However, physical checks will be carried out at points of entry at ports in Northern Ireland - mainly in Belfast and Larne.
Dr Huey urged anyone who moves animals or goods from Great Britain to Northern Ireland to read the new guidelines as soon as possible.
"Individuals and businesses should thoroughly read the Compliance Protocol and the Guidance for Authorised Traders and understand what they need to do to keep trading," he said.
"While some of the new processes will be phased in over time, many of them start immediately - therefore people should read these guides as soon as they can.
"It is clear how complex the food, animal and plant supply chains are and these documents explain how to navigate the changes. They set out how to move food, animals and plants and aim to bring all the various parts of the journey together to prepare traders for the new requirements. We will of course work with traders as much as possible.
"There is a section on pet travel, which everyone who wishes to travel with their pet should read and familiarise themselves with, to ensure they adhere to the new regulations."