Mark Dunford is believed to be "the main man" referred to by other suspects arrested following a surveillance operation stretching from Coleraine to the north west of England, prosecutors said.
The 38-year-old faces charges of conspiracy to supply Class A, B and C drugs, and encouraging or assisting offences.
Dunford, of Ballylagan Lane, Coleraine, was detained last month as part of an ongoing investigation into a number of seizures made last September.
During a failed application for bail a judge was told how amphetamines with an estimated street value of 20,000 were recovered from a car being driven by a co-accused in Ballymena.
A jar containing 1,100 Ecstasy tablets worth £11,000 was later found under shrubs in the front garden of that suspect's home.
As part of the same operation another man was arrested in Coleraine after cocaine valued at £15,000 was seized from another vehicle.
Further searches of a transit van led to the discovery of nine sealed bags of amphetamines inside a household oven.
According to the prosecution those drugs weighed 2kg and are estimated to be worth at least £180,000.
A small quantity of cannabis and scales were recovered from the second man's home.
Dunford was arrested after that suspect claimed he was told to collect the oven during a telephone conversation with "the main man".
Prosecution barrister Kate McKay alleged that call data and cell-site analysis links Dunford to the operation.
She said police believe a mobile phone used by the suspects travelled with him on a trip to England eight days before the initial arrests.
English police were also involved in a surveillance operation of a meeting he was at in Manchester, according to Mrs McKay.
The court heard how Dunford, originally from Waterford in the Irish Republic, has set up a gym in Coleraine where he now lives with his family.
Opposing bail due to the risk of any further offending and fears that he could flee, Mrs McKay said he is suspected of being linked to an English-based crime gang.
"Police do believe he is, and I will continue to use this term, the 'main man'," she said.
Defence lawyer James Johnston argued that only a weak circumstantial case based on alleged telephone contact exists against Dunford.
He claimed police had "latched onto" a mobile phone number, adding that there was no link to the actual drugs seized.
Mr Justice Maguire was told the gym Dunford has been running since last year faces closure if he is kept in custody.
But refusing bail, the judge held that his release could lead to the risk of further offences.