Two top runners will visit Rotorua as they look to conquer five marathons in just five days.
Personal trainers Greig Rightford and William Tokona, from Wellington, are running the marathons across five different cities.
The pair will run their fourth of five marathons in Rotorua on Thursday, starting at the Redwood Forest visitor centre on Long Mile Road at 5.30am.
Locals are invited to run alongside the pair as they look to raise interest and money for their chosen charity - the Malaghan Institute of Medical Research.
The five-day run will also be a mental and physical test for the pair before they leave to the Sahara Desert in April, to race in the Marathon des Sables (Marathon of the Sands).
The 234km Marathon des Stables is widely recognised as the toughest footrace in the world.
The race is held in 40C temperatures across six stages.
Mr Tokona said they chose Rotorua as one of the five marathon destinations because they had enjoyed racing here in the past. He said they tackled the 100km Tarawera Ultra Marathon last year, finishing in the top 20.
Mr Rightford has also raced in the Rotorua Marathon on several occasions.
Recent training has not been easy for the pair, with Mr Rightford breaking his neck in a mountain bike accident in October and Mr Tokona injuring his hamstring.
"We want to attempt this feat anyway, despite the risks," Mr Rightford said.
"We look forward to ordinary runners throughout New Zealand joining us, to both support the Malaghan Institute and learn more about the Marathon of the Sands."
The pair will be doing two laps of the Blue Lake, taking in the Redwoods, and said locals could meet them at the Redwood Forest visitor centre at about 8.30am for the second lap if the start time was too early.
The marathon runners will take in Dunedin, Christchurch, Auckland, Rotorua and Wellington during their five marathons, starting on Monday.
The Malaghan Institute of Medical Research is a New Zealand organisation which focuses on cures and treatments for diseases and conditions such as cancer, asthma and arthritis.
The pair hope to raise $50,000 for the charity. To donate visit www.fundraiseonline.co.nz/SaharaCharityChallenge2013/