The event has consistently raised over $1 million in each of the last four years.
Not for the unfit or faint-hearted, training recommendations include steep hills, sand dunes rowing and weight training.
It's also a good idea to train in a heavy jacket and pants.
The Waihi team has been preparing for this year's event as individuals and as a team.
Recently the team climbed Mount Maunganui, which at 232 metres, is still only two-thirds of the vertical height of the Sky Tower.
The current record for the climb is eight minutes 34 seconds, held by a competitor described as 'an ironman machine'.
Members of the Waihi team aim to complete the climb in 14-15 minutes, raising around $18,000 in the process.