Foveaux Strait, the body of water between Bluff and Stewart Island, is one of the most dangerous stretches of water in the country
To date, only nine people have managed to swim across it, a journey that can take anywhere between eight-and-a-half and 14 hours.
Next month, Hannah Morgan is hoping to become the tenth to swim Foveaux Strait as part of her drive to improve mental health awareness across New Zealand, and raise some much needed funds for charity.
Morgan spoke to Duncan Garner.
Watch the video.