Pickersgill explained how the fire happened on the food truck's Facebook page.
"It's with a very heavy heart I share this news," he said.
"We were just out of Bob's Cove 20 minutes South of Queenstown after having an awesome day serving BBQ to 70 beautiful people when the truck started smoking.
"We didn't even have a chance to save her - we just had enough time to unhitch the Jeep, get space between us and the truck and watch her burn."
Pickersgill said the emergency services were quick to the scene but it was too late.
"Without a doubt one of the saddest moments of my life and right now - I am absolutely gutted.
"To all the people who have booked us over the coming months - my sincerest apologies, I'll be reaching out to you all over the coming days.
"This isn't the end, we will rebuild."
The food truck is well known in the Canterbury area and beyond and is touted as the first American BBQ truck in the South Island.
Pickersgill custom-built the food truck after multiple trips to America and teaching himself the art of BBQ cooking.
"First set up in Methven, then moving to Queenstown and now Christchurch, Truck Norris is an iconic name, and well respected business in the culinary-truck industry," the website says.
A Givealittle page has been set up to help Pickersgill rebuild.
"Matt has insurance for the truck, but it's capped including catering equipment contents - it's limited insurance," the page states.