Police say they were investigating reports of a bomb on a lorry due to travel by ferry from Belfast to Scotland, before a device was discovered in Lurgan.
Police and the haulage company eliminated around 400 vehicles in a bid to locate the explosive device.
The device was subsequently found attached to a heavy goods vehicle in the Silverwood Industrial Estate and was later made safe by army technical officers.
Police say the device could have exploded at any point along the M1, across the Westlink or into the Harbour estate.
Detective Superintendent Sean Wright, PSNI’s Terrorism Investigation Unit said police first received a report on the evening of Friday, 31 January that an explosive device was in a lorry in Belfast docks.
“That report informed police that the lorry was due to travel by ferry to Scotland. Based on this information police conducted checks of the docks area and worked with the ferry company, Belfast Harbour authorities and Police Scotland to try to locate that device. After thorough checks nothing was found. The ferry sailed and arrived safely in Scotland,” he said.
He said police received a further report on Monday that the bomb had been attached to a lorry belonging to a named haulage company.
“This more detailed information enabled police to conduct focused investigations with the haulage company. Working throughout Monday and Tuesday police and the haulage company eliminated in the region of 400 vehicles in order to locate the explosive device,” he added.
And he said that Dissident Republicans deliberately and recklessly attached an explosive device to a heavy goods vehicle in the full knowledge and expectation that it would put the driver, road users and the public at risk of injury and possible death.
“Had this vehicle travelled and the device had exploded at any point along the M1, across the Westlink or into the Harbour estate the risks posed do not bear thinking about. The only conclusion that we can draw is that once again Dissident Republicans have shown a total disregard for the community, for businesses and for wider society,” he added.
And Detective Superintendent Wright is appealing for anyone who was in Silverwood Industrial Estate between 4pm and 10pm on Friday, 31 January and who may have noticed any unusual activity in the area to contact police.
“In addition I ask that anyone who was driving in the area and who would have dash-cam footage around these same times that they contact police, as a matter of urgency.
“Police can be contacted on the non-emergency number 101. Alternatively, information can also be provided to the independent charity Crimestoppers on 0800 555 111, which is 100% anonymous and gives people the power to speak up and stop crime,” he added.