The pair were one of many teams at the Bungendore Showground over the weekend taking part in the trans-Tasman Sheepdog Trials.

"Tom's so fast at this we had to chop off one his back legs just to hold him back a bit," Mr Chalmers joked.

"But really, he does as good a job as any out there. His only handicap is me."

The trials are a competitive affair where dogs guide sheep through a series of marked obstacles and into a fenced pen at the end.

At least that's how it's meant to work in theory, veteran herder Charlie Cover said, with the results sometimes far more calamitous.

While a good herder could calmly guide the sheep through the paddock in an orderly procession, a bad one could spook them and scatter them to all corners of the field.

"The art of trialling is getting the balance right between having the sheep in a state of fright and a state of flight," Mr Cover explained.

"Sheep are basically the prey and the dogs are basically the predator. But you've got to try and dampen that instinct down a little bit."

Mr Cover, from Yass, has been training sheepdogs most of his life and is a bit of a legend in local circles.

On Sunday he put border collie Ella through her paces, no mean feat considering she is more lapdog than farm dog.

"I took her out to the farm one day and realised she had some ability," he said.

"Almost every other dog here trains far more often. Ella might train with me once or twice a week.

"But as soon as she sees me she knows there are sheep about."

Like any sport, the trans-Tasman rivalry between Australia and New Zealand is a healthy one.

"People joke about the sheep industry in Australia being started by convicts from London," Bungendore Sheepdog Club member Bruce Bashford says.

"While in New Zealand it was started by shepherds from Scotland."

There will still plenty of punters turning out to catch the action on Sunday.

"We've got quite a few people out here actually, it's good," Mr Bashford said.

"There is certainly plenty for people to see."