AFL FOOTBALL operations boss Mark Evans says the strengthening of the deliberate out-of-bounds rule has been a success, but admits an error was made in Friday night's North Melbourne-Western Bulldogs clash.

A clearing kick out of defence from Western Bulldog Mitch Wallis led to a foot race on the wing between North defender Luke McDonald and Dogs midfielder Liam Picken in the final minute of the third term.

The pair chased the ball towards the boundary line in front of the interchange area, with McDonald gaining possession of the ball right on the boundary line.

McDonald had no option to keep the ball in play but his actions were deemed deliberate under the AFL's more stringent out-of-bounds interpretation that was introduced this season.

On Monday night, Evans said in this instance the ball should have been thrown in, acknowledging McDonald should not have been penalised.

"I think the deliberate rule has been pretty good, but that's not one of our most crowning bits of glory," Evans told Fox Footy.

"The umpire's coming from the centre of the ground and he wouldn't be aware whether Luke is crossing the line.

"It's just too hot to call that."

The tougher interpretation has contributed to a more free-flowing spectacle in the first six rounds of the season.

Evans said players were now required to show more intent to keep the ball in play under the stricter rules.

"We've certainly lowered the hurdle that you have to jump for this, so it's not now about whether it's deliberately taken over the boundary so much as where we can say, 'Was there enough intent to keep the ball alive?'" he said.

"We have to now see some intent from the player to keep the ball in play."

Meanwhile, Evans said the League was continuing to investigate the stretcher incident that saw play halted in the dying minutes of the Brisbane Lions-Sydney Swans clash last Sunday.

Ump wrong on stretcher incident: AFL

He added that the emergency umpire was at fault.

"The biggest issue for us is that it was an error from our emergency umpire, who blew the whistle to say that the stretcher was coming on the field," Evans said.

"Now, an emergency umpire should never blow the whistle."