Irish horses racing in the Grand National face being quarantined for as long as six months.
The six horses, including last year's winner Papillon, were due to be shipped to the UK on Thursday, but rough seas prevented their passage.
They will instead fly from Dublin to Liverpool on Friday.
Irish Agriculture Minister Joe Walsh had originally banned horses travelling to prevent the risk of spreading foot-and-mouth.
His decision to lift the ban was announced on Monday but he insisted horses be quarantined for an unspecified period.
Aintree spokesman Nigel Payne said: "The horses must stay in the UK for an as yet unspecified period after the last confirmed case of foot-and-mouth.
"That could mean they will be here for anything from a month to six months."