Speaking at Dun Laoghaire on the Irish coast on Monday, Mr Harris said it was "a serious concern to both people who've bought goods and presents and gifts that they're hoping will arrive, and also people that are understandably trying to get home for the Christmas period".
Port operator, Stena Line has apologised for the cancellation of its Holyhead sailings, adding that it was "doing everything in its power to mitigate the effects of the closure on passenger and freight traffic".
There are normally four daily ferry sailings going each way between Holyhead and Dublin, operated by Stena Line and Irish Ferries.
The closure had led Ireland's national postal service to abandon plans to use Holyhead port for Christmas deliveries.
Mr Harris said "a huge amount of work is ongoing in government on this issue", including a meeting between the minister for transport and the minister of state for transport and their Welsh counterparts.
Ireland's junior minister at the Department of Transport James Lawless met his Welsh counterpart Ken Skates on Sunday and both are due to meet with Stena Line at 13:00 GMT on Monday.
Mr Lawless said both ministers are asking for Stena Line to give more "accurate and timely" updates on the scale of the damage and repairs needed at Holyhead.
He said Mr Skates had committed to also temporarily relax driver rules as had been done by the Irish government over the weekend.
Ireland's Department of Transport announced that it would ease rules around haulier hours until 27 December, allowing drivers to do more hours and take fewer breaks.
Mr Lawless said that this being introduced from both sides at Holyhead would help to clear the backlog of deliveries.