Both legs are in plaster and he will have to undergo surgery to reconstruct his right heel. The injuries will delay his return to Wales, but will not hamper preparations for the summer tour to Australia.
"Warren's return to Wales has been delayed as he recovers from leg injuries sustained in a fall while working at his family beach house on Waihi Beach at around 8.30am (New Zealand time) last Easter Monday morning," explained a WRU spokesman.
"He was cleaning windows when he lost his balance and fell three metres onto concrete, taking the full impact on his heels. He suffered multiple fractures to the right calcaneus and also a fracture to the left calcaneus.
"Consequently, he is in leg casts and requires surgery by the leading orthopaedic surgeon in the Waikato to reconstruct his right heel. The injury he suffered is not expected to have any major impact on the continuing preparations for scheduled Wales matches in June 2012."
The calcaneus is the bone in the back of the foot, commonly referred to as the heel bone. This bone helps support the foot and is important in normal walking motions.
The joint on top of the calcaneus is responsible for allowing the foot to rotate inwards and outwards. Calcaneus fractures usually occur as a result of a fall from a height, such as falling from a ladder.
"While in New Zealand, Gatland will continue to receive information primarily from Rob Howley, Robin McBryde, Shaun Edwards and Neil Jenkins as they observe and monitor squad players and potential players over the next few weeks," added the spokesman.
"Assistant Coach Rob Howley will oversee day-to-day management of the coaching staff in Wales and will play a key role in liaising between the Wales-based staff and the Head Coach during Gatland's temporary absence from camp. Team Manager Alan Phillips will keep the Head Coach informed of all other squad preparation issues."
The WRU Group Chief Executive, Roger Lewis, has approved the plan for temporary injury cover and he has indicated that although there is no current requirement for any of the staff to be appointed caretaker Head Coach, he and Gatland have agreed to recommend to the WRU Board that Howley would fill the role if required.
Although it could be several weeks before he fully recovers he is expected to be able to return to active coaching duties before his recuperation is complete.
"Knowing Warren as I do I can reassure the Welsh rugby public that he has diligently put the people and processes in place to ensure he stays closely linked to what is happening in the game back here in Wales," said WRU chief executive Roger Lewis.
"I have spoken to Warren on a number of occasions since his fall and have told him he will lead the tour to Australia unless anything unforeseen happens in the prognosis for recovery we are working to."