"A two minute sit-stay can seem a very long time. It doesn't matter how many times you do it perfectly at home, it can all go wrong on the day.
"We occassionally get dogs wandering off. So many great smells, too many distractions."
Anyone who has ever watched Crufts knows that even the best competition dogs have their off days. To be clear leaving doggy-doos on the course is frowned upon.
Unlike Crufts, at the Master's there's a silver lining. Spot prizes are handed out for those embarassing but funny departures from plan.
"Two year's ago we had a dog jumping a two rail fence. Instead of jumping over both rails he went clean through between them without dislodging either one. I'd never seen that happen before."
Entry numbers are down a bit this year, Mr Stewart said.
Two clashing agility competitions are taking place in Wairarapa and another at Cambridge, luring away some who would have otherwise have competed at the Master's.
"We have 33 entered so far. Last time we had competitors from the South Island but none so far this year."
So if you were thinking of entering Fido, now might be a good time.
"There needs to have been some level of training. But the Master's is about having fun and is more relaxed."
Competitors could give themselves a big advantage simply by owning the right breed.
Wikipedia ranks Bordie Collies as the smartest of dogs, followed closely by Poodles, German Shepherds and Golden Retrievers.
Avoid Bullmastiffs, Bulldogs, and the dimmest breed of all, the Afghan Hound.
"Working breeds tend to do well at dog handling. Hard core competitors breed dogs especially for the sport," Mr Stewart said.
This year's event takes place on the last weekend of the games over February 11-12 at Otamatea Reserve on St John's Hill.
Agility is the most popular of the four categories with obedience second. Cross country and Rally-O are also being offered. Rally-O is fairly new and is a cross between agility and obedience.
Togs or at least a towel might be advisable items for competitors to take along. In the cross country a paddling pool must be waded through, if not by canine, then by its handler. "That obstacle ofen gets a laugh."
Competitions start at 8.30am both mornings. Girl dogs on heat must stay at home.
The Masters Games are in Whanganui from February 3 to 12.