But if unused, this reserve produce "is offloaded to anyone that will take it".
And as Ireland exports meat and dairy produce to the UK in refrigerated containers anyway, transporting produce back to Ireland "is never a problem", he claimed.
"A strong euro against sterling in recent times and lower labour costs in the UK don’t help the situation," he added.
In 2011, Ireland imported €324 million (£260 million) worth of fruit and vegetables from the UK - a sum almost as great as the entire Irish horticulture sector, valued at €380 million.
"It’s not a fundamental lack of competitiveness that is the issue," Hackett said.
"It's more a matter of the drop from one big market becoming a torrent in the adjacent small market."