It is not yet known if they were local to the area.
Police would be working with WorkSafe to investigate the death, Mr Sutton said.
Principal rural fire officer Phill Wishnowsky said a Masterton fire crew and two ambulances were dispatched to the scene.
A Life Flight Westpac Rescue Helicopter also attended, despite wind gusts of 160km/h, Mr Wishnowsky said.
The firefighters would be offered counselling as part of standard procedures, he said.
"We are making sure that they have the support that they need at a time like this."