Tourism company SeaLink Travel Group has halted its Captain Cook Cruises operations on Sydney Harbour and embarked on cost-cutting across its broader operations, as it withdrew profit guidance amid escalating uncertainty from the coronavirus pandemic.

SeaLink chief executive Clint Feuerherdt said on Friday that about 85 per cent of the group's overall revenues came from the Transit Systems business, which operates 40 long-term bus contracts for governments around Australia, but the tourism division was facing very tough times.