The competition watchdog is taking Tasmania's state-owned ports operator to court over alleged anti-competitive conduct.

The ACCC alleges that TasPorts, which owns all but one port in northern Tasmania, sought to stop a new entrant, Engage Marine Tasmania Pty Ltd (Engage Marine), from competing effectively with TasPorts’ marine pilotage and towage businesses, with the purpose, effect and likely effect of substantially lessening competition.

“In short, our case is that TasPorts sought to maintain its monopoly in towage and pilotage in Tasmania, resulting in higher prices and lower quality services,” ACCC Chair Rod Sims said.

“This is the first case under the amended misuse of market power provision, an important law reform designed to protect the competitive process and help us address the harm that anti-competitive conduct does to consumers and the Australian economy.”

The ACCC alleges that TasPorts prevented Engage Marine from expanding in Tasmania by failing to provide long term berths for its tugboats, and refusing to place Engage Marine on the shipping schedule, which is necessary for it to provide towage services.

The ACCC also alleges that TasPorts has prevented Engage Marine from providing pilotage services at Port Latta by failing to provide training to Engage Marine’s employees, which only they could provide, and demanding that Engage Marine’s sole customer pay about $750,000 a year in fees to TasPorts after the customer stopped contracting with TasPorts.

“We are alleging that TasPorts’ actions are driven by an anti-competitive purpose, and that its conduct has had or is likely to have an anti-competitive effect,” Mr Sims said.

TasPorts issued a statement saying the issues raised by the ACCC were “based on unique situations; they involve a law that has not yet been tested”.

A date for legal proceedings in the matter has not been set.