More than 300 jobs are at risk at online bike retailer Wiggle CRC.
The company plans to concentrate most of its warehouse facilities in Wolverhampton.
The proposals are due to be introduced late next summer, a statement said.
“This necessary step will require the relocation of significant warehouse activities currently in Doagh, Carrickfergus and Ballyclare.
“As part of this proposal, bikes and frames, including bike assembly handling activities and our wheel build operation would remain in Ballyclare.
“A consultation process will shortly commence with the 152 potentially affected employees and their representatives.
“Discussions will also start with agency management in respect of the 161 agency workers currently supporting warehouse operations in Northern Ireland.”
The statement added that delivery, including later order cut-offs and speed, was becoming increasingly important for customers and a highly competitive area for all retailers.
“For Wiggle CRC to retain its position and remain competitive in the UK as well as increasingly global markets, we have concluded that this can be best achieved by concentrating the majority of our distribution through our warehouse facility in Wolverhampton.”
Wiggle CRC was formed when Wiggle took over Doagh-based Chain Reaction Cycles earlier this year.
Ulster Unionist Assembly member Steve Aiken said he was shocked.
“The story of Chain Reaction Cycles has, up to now, been one of continual expansion and success.
“This will also significantly affect the Royal Mail as Chain Reaction have been one of their biggest customers.”
Unite regional officer, Davy Thompson blasted the move as “a clear case of corporate asset-stripping”.
“Wiggle acquired its competitor in February of this year and by October wants to close most of its Northern Ireland operations.
“Earlier in the year, Unite reps raised concerns with political leaders that Wiggle’s acquisition might be driven by a desire to buy a competitors’ order-book with little long-term commitment to its workforce. We were given assurances that this was not the case.
“Corporate actions like this would incur huge costs in most European countries, where employers have to contribute to the social costs of the dislocation caused by disinvestment and redundancies; such protections are no barrier to the success of those economies – there is no excuse for inaction.