The Department of Infrastructure says revealing how much it charges a charity to rent land in Ramsey could undermind future negotiations.
A Freedom of Information request to the department asked how much it charged the Manx Wildlife Trust for two plots at the Hairpin Woodland Park.
But the DOI says the information is commercially sensitive and won't be released.
Earlier this month, the charity said it had signed a 95-year lease for the land, which forms part of a Biosphere project.
Castletown police station could be yours... for £250,000
Brewery advertising for operator for landmark Laxey pub
Hospice cafe reopens next week after refurb
Another one bites the gust - as Ramsey rocks cancelled
Mountain Road closed again after crash
Merchant Navy Day to be marked with memorial service
Fundraiser launched for injured MGP rider
Noel back in the saddle after handy pub pumping leaves him smiling