Transport Canada says the Detroit-Windsor truck ferry should be back in service by the end of March.
The ferry, which shuttles transport trucks carrying dangerous goods across the Canada-US border, shut down in November for repairs.
The ferry usually runs 10 times daily from Windsor to Detroit, carrying up to eight trucks at a time.
Drivers have been forced to use the Blue Water Bridge at Sarnia, Ont., because the Ambassador Bridge at Windsor does not permit the transfer of hazardous goods.
Work on an $8.8-million dollar expansion to the 20-year-old facility was supposed to have been completed by mid-February.
Transport Canada and the Ontario Ministry of Transport are funding the upgrades.
A spokesman for Transport Canada said improvements on the Canadian side have taken longer than expected.
"You're working in water...it's difficult when you have ice conditions and there's freezing," said Nino D'Allesandro. "The production rates are slower in the winter."
Ferry operators hope the expansion will allow them to increase trip frequency and improve security.