USAR teams working after the Christchurch quake. File Photo / Rocky Batchelor

Urban Search and Rescue teams spent a month crawling through suffocating spaces, often cold and wet in the pitch black, breaking through concrete walls in pancaked buildings in a desperate effort to find survivors and bodies after the Christchurch quake.

It is those conditions that trainee USAR member John "Ruckus" O'Rourke knows lie ahead of him as he trains to become an internationally certified USAR member.

More than two dozen firefighters and paramedics are undergoing training at an abandoned freezing works factory in Feilding in conditions designed to mirror the horror scenes that resulted from Christchurch's 2011 quake.

At the end of the three-week course, they will be trained to international standards and will be part of the USAR team that will work here as well as being deployed internationally.

Mr O'Rourke said it was the hardest thing he had ever done.

"I didn't realise how hard it was going to be physically and mentally.

"But it's the most charged up I've ever been on any fire service course."

The Christchurch firefighter was inspired to join the team after seeing first hand the devastation an earthquake could cause.

He acknowledged the work would put his life on the line - and in the training exercises they did not have to cope with other challenges such as aftershocks.

"So that's always in the back of your mind..but I think everyone here is looking forward to getting into it."

Two teams are halfway through a 72-hour training exercise in which they work 12 hour shifts breaking through concrete, building safety structures, crawling through crevasses no higher than half a metre high and 'rescuing' trapped victims.

USAR Commander Ken Cooper said the challenges were typical of what teams working in the aftermath of the Christchurch earthquake faced.

Around the site tons of twisted concrete replicated collapsed building facades and destroyed carparks.

Waterlogged underground tunnels were filled with whiteware, furniture and concrete tunnels the teams had to work through, sometimes with only having had three or four hours sleep.

"The psychological effects are far greater than the physical," Mr Cooper said.

Also going through his paces is Luna, the service's first cadaver dog.

Dog trainer Tim Drennan said Luna was trained by using the scent of a dead person that was shipped over from the United States.

The team realised the importance of a cadaver dog after the Christchurch quake.

"We put all our energies into live find dogs, but after a few days we found we needed a cadaver dog."

Bernie Rush, part of the USAR management team said the training simulated the "worst possible" search conditions.

"During the course we've taught them stress management techniques and just monitor them as part of the final examination process to see that they apply those techniques when they start getting tired and sleep deprivation starts kicking in."

Mr O'Rourke said his team members weren't in it for the glory "they just want to do the job and help people".

* USAR was started in Palmerston North in 1995;

* initially they were trained by members of the Federal Emergency Management Agency (FEMA) from the US;

* there are 24 firefighters on the course and six paramedics;

* there are 220 USAR members based in Auckland, Palmerston North and Christchurch;

* the team has $1.5 million worth of equipment; and

* it costs $4,500 to outfit each team member.