More than half of the companies that Revenue feels should have engaged with them regarding the impact of Brexit have not been in contact, according to the head of Revenue's Brexit policy unit.
Revenue officers will be boarding ferries from tomorrow to provide face-to-face information to truckers about the impact of a no-deal Brexit.
Speaking on RTÉ's News at One, Lynda Slattery said these officers will offer advice to truckers about what they need to bring to the ports to ensure they can board vessels in the event of a no-deal Brexit and also about how they will know which customs channel to use.
She said this would prevent truckers from arriving at ports without the correct documentation.
Ms Slattery said doing so could have a very serious impact, particular if the lorry contains perishable goods.
"If these are perishable goods they run the risk of losing that load because they will be turned away," she said.
However, she said a lot of companies have not engaged with their Brexit preparation services, particularly in the construction and manufacturing sectors.
"We are doing everything we can to make sure trade know what the changes will be and how they need to operate from after the 12th.
"We are reaching out as much as we can, we have the capacity to respond to businesses coming back to us - our doors are open and we are waiting to engage and proactively going out to them. Really I would strongly encourage them to be engaging with us now."
Speaking on the same programme, Minister of State at the Department of Finance Patrick O'Donovan described the decision by Revenue to post officers to Dublin and Rosslare ports to meet hauliers face-to-face as "very proactive".
Mr O'Donovan said: "Every person in the country is practically talking about Brexit, it is up there with the weather, so it is very important that the 42,000 odd companies would engage with Revenue".