The fire broke out Saturday night about 30 miles from land, forcing the ferry to turn around to North Shields, the Independent reported.
"At approximately 11 p.m. the Maritime and Coastguard agency informed Humberside Police that a passenger ferry en route from Newcastle to Holland had suffered an incident whereby a passenger is believed to have set fire to a cabin," Inspector Andrew Dixon told the newspaper. "It is unknown if the fire was started deliberately or accidentally. As a result of this incident the person suspected of causing the fire, or the person from the cabin where the fire occurred, be it deliberate or accidental, has been detained by ship staff and the ship was returning to its dock in Newcastle."
The second person was arrested for fighting after the fire broke out.
Two crew members and four passengers were airlifted to hospitals for treatment of smoke inhalation and another 15 passengers and eight staff were checked out by a doctor on the ferry, officials said.
Gert Jakobsen, a spokesman for the Danish ferry operator DFDS, told the BBC customers who were unable to travel to Amsterdam would be refunded.
"We will do everything to help our passengers. There will be a ferry leaving tonight, there will be some spaces on that [and] there will be some spaces offered on other ferry lines," Jakobsen said. "We hope to help as many as we can."