Prosecutors disclosed that the drugs were hidden in wooden containers fitted under the vehicle which travelled north after arriving on a ferry in Dublin.
Details emerged as bail was refused for a Manchester-based driver accused of being part of the alleged distribution plot.
John Hill, 50, of Whit Lane, Salford, faces charges of possessing cannabis with intent to supply, conspiracy to supply and importation of Class B drugs.
He was one of five men arrested when police swooped as a van was being unloaded in Carrickfergus, Co Antrim last August.
Officers recovered 17 kilos of herbal cannabis in the operation, which have an estimated street value of around £350k.
Prosecution barrister David McClean said specially-made boxes had been fitted to conceal the illegal shipment.
The vehicle had crossed on the Holyhead to Dublin ferry after being driven from England by Hill, the court heard.
The accused mounted a new bid to be released on bail due to delays in the case, with a preliminary enquiry to establish whether he will stand trial put back to 19 June.
But Mr McClean questioned his claim of having no knowledge of the drugs by alleging that more cannabis was recovered during a search of his home.
It was also set out that Hill made 13 ferry bookings last year despite being unemployed.
Tom McCreanor, defending, argued that other co-accused have been released, including the alleged "local contact" who was unloading the boxes.
But Mr Justice Deeney refused bail due to the combined risk of flight and re-offending.
"There is a strong case of a sophisticated drugs operation," he said.
However, the judge added that it was "unsatisfactory" that the preliminary enquiry has not yet taken place.
Stressing that no blame was being attached to the police, he said: "The prosecution service are living in the last-ditch saloon so far as delay in concerned.
"This preliminary enquiry had better happen on 19 June, or I will grant him bail the following day on grounds of delay."