A frustrated NSW Waratahs coach Michael Cheika has called on officials to limit rugby union's time-consuming scrums to 30 seconds after Saturday's last-gasp loss to the Brumbies.

The Waratahs fell agonisingly short of reeling in a 16-point deficit in the final 20 minutes of their 28-23 Super Rugby loss in Canberra, and Cheika has no doubts what aspect of the game cost his side precious minutes to deliver the finishing blow over their grudge rivals.

"The amount of time it's taking to set the scrums. It's just taking far too long," Cheika said. "You want the ball in, you want to play, but we wasted an unbelievable amount of time at scrummage. Everyone would like that, me included, especially when you're chasing games."

New scrum laws have been introduced in 2014 to help increase actual game time, with the "crouch, bind, set" system requiring packs to bind in advance and stay stationary until the ball is in. But Cheika wants to speed things up even more.

He raised the issue with SANZAR game manager Lyndon Bray at the referees' meeting at the start of the year - but has heard nothing back since.

"We asked if we could bring in a rule from the time the whistle blows, by 30 seconds the ball should be in," Cheika said. "It was a good idea at the time and everyone was there, but that was it."

Cheika also drew issue with penalties awarded at the scrum. There were 14 scrums in Saturday's match, the Brumbies winning all five of their own, as well as earning penalties in several of the Waratahs' nine feeds.

"There's just inconsistency across the board around who's collapsing, who's wheeling," Cheika said. "I was really disappointed with the scrum at the end there that they got given again, when really that ball should have been given to us."

A frustrated waratahs coaching box. The result of a Brumbies 28-23 win pic.twitter.com/G65mNxEQGI

— Chris Dutton (@BlockaDutton) March 15, 2014

While the ensuing penalty goal from that scrum shut the door on the Waratahs, that didn't stop Cheika from all-too-hastily opening one of his own. He stormed out the of the coaching box with such force that he accidentally splintered the laminated glass door.

The loss means the Brumbies are the new leaders of the Australian conference, although the Waratahs trail by just two competition points with one extra game to play.