''We set up our two-man tents and then a church group came around handing out sandwiches,'' he said. ''The food was beautiful but it was unexpected.''

Central Christchurch was a surreal ghost town; residents had been evacuated to maintain law and order and to keep them out of harm's way and the bulk of the international relief effort had yet to materialise. ''By the time we left [13 days later] the park had become The Red Zone,'' Perks said. ''There were more than 1000 people there.''

He describes entering the sealed-off CBD for the first time as an eerie experience. ''Everybody had been moved out; there was food on tables, money on counters, banks had been left with their vaults open and there were crushed and abandoned cars everywhere. It was like being in an end-of-the-world movie. You had to pinch yourself to remind yourself it was real.''

The experience became even more surreal when Perks and his partner, Matt Spackman, drew the night shift. Probing the ruins of an abandoned city for the living and the dead in the middle of the night is not an exercise for the faint-hearted; particularly when recurrent aftershocks are sending fresh cascades of broken glass and debris into the streets every few minutes.

Perks was awake for 48 out of the first 52 hours he was in New Zealand and saw and did things he hopes never to repeat.

''We located seven deceased in the first three nights we were in rescue mode,'' he said. ''I found two victims under desks and a lady and her 18-month-old baby who had been crushed under an awning.

''We were watching the news later and her husband was being interviewed, saying he hoped she would be found soon … I just thought 'he doesn't know, they haven't told him'.''

The Australians were among the first non-New Zealanders to reach the devastated city and members of the first part of USAR 1 had pulled the last survivor out of the ruins just before the Hercules carrying Perks and his mates left Richmond Airforce Base in Sydney.

The 38-year-old Canberran had left behind his wife Danielle, who was five months' pregnant with their son Jed, and two young daughters, Paris, then 8, and Ada, then 4. He was to think of them often during the days ahead, constantly reminded by the tragedy around him of the transience of human life and how quickly you could have everything stripped from you.

''Of course I thought about it [the risks],'' he said. ''I thought about it one night when we were in the stairwell of a collapsed building that we had been told no amount of shoring would make safe and we were hit with a 4.8-magnitude aftershock.''

On another occasion, about three tonnes of rubble fell into a doorway Perks and other team members were about to enter.

Loss and grief were everywhere. A volunteer crane operator assisting at the search of the ruined PGC building continually asked rescuers ''did you find her?'' as they emerged from the rubble pile. He was desperate for news of his sister-in-law who had been trapped when the building collapsed and refused to leave until she was found.

''When you have someone like that it is often better to put them to work [than to try to have them removed],'' Perks said. ''He was quite useful as the crane operator.''

Darren Neville, an ACT ambulance paramedic and urban search and rescue volunteer who travelled to Christchurch as part of USAR 3, has nothing but praise for what Perks and the other members of the first two taskforces achieved.

As a paramedic he was responsible for looking after the welfare of the other team members as well as fulfilling the urban search and rescue role. Because of the strong emphasis on safety during training there were no serious injuries among the Australian rescuers although cuts, abrasions, sprains and blisters were not uncommon.

For Neville, like Perks, the second anniversary has come around quickly. ''It still seems like it was yesterday,'' Neville said.

Perks agreed: ''It takes a long time to get those images out of your head. For the first year I would have been revisiting them every day.''