Tui Travel and Thomas Cook’s businesses in the Netherlarnds are being investigated as part of a sector-wide price-fixing probe in the country’s travel industry.

The Dutch competition regulator NMa is investigating all travel companies in the Netherlands for price fixing. Tui Travel is the country’s market leader.

A spokeswoman for Tui Travel said: “The investigation is about agreements between companies which are not allowed. We have nothing to hide and we are co-operating fully with the investigation. We are confident of the outcome.”

Tui’s business in the Netherlands includes the tour operator brands Arke, Holland International and KRAS. It also has an airline ArkeFly and more than 200 Arke travel agencies. The Netherlands business reported an operating profit of £7 million for 2010.

A spokesman for Thomas Cook said:  “Thomas Cook confirms that its Dutch subsidiary has had an inspection by the Dutch competition authorities (NMA) regarding the pricing of short haul overseas holidays in Holland.  Thomas Cook is co-operating fully with the NMA.”