The trickiest part of the route is the ominously named Demon Trail (10km) alongside Lake McKerrow.

BBC: New Zealand��s tracks less travelled

Options for reducing the length of the there-and-back journey include hitching a jetboat ride south with Hollyford Track Guided Walks for the length of Lake McKerrow (book in advance).

BBC: New Zealand��s tracks less travelled

June McKerrow, director of the Mental Health Foundation, said that, although some of the illnesses included in the report were temporary and mild, research suggested that if they were not properly dealt with they could develop into something worse.

BBC: One child in five 'mentally ill'