Australian captain Cameron Smith admitted he told his players to wait and wind down the clock at various stages of the NRL All Stars match in Brisbane on Saturday night.

The new rule means players must assemble for a scrum in 35 seconds, and 30 seconds for a drop-out restart. The clock is shown on the big screen at stadiums for players and fans to see.

It was designed to keep games flowing but there were a number of occasions at Suncorp Stadium where all the players were ready to pack a scrum but instead, they waited out the duration of the shot clock.

Whether players are as energetic in NRL games minus the unlimited interchange available on Saturday (and 20-minute quarters) seems doubtful but it will provide urgent food for thought for the game's administrators as the season looms.

"I'll be honest with you, I thought it gave us a chance to have a rest, if anything. There were a few times there early on when we were at the scrum with about 25 seconds left on the clock," Smith admitted after the game.

"I used my brains a bit and told the boys to wait another 20 seconds. It might change a little bit. It might be different when you take that unlimited interchange out of the game and there are some tired bodies getting around.

"But that's the way it panned out tonight."

World All Stars coach Wayne Bennett said the rule may need a second look before the season starts and referees may have to penalise teams deemed to be dragging the chain on the way to scrums.

But that could be difficult. The clock is there for all to see and all it would take is for a few stragglers to arrive late to ensure it was fully utilised, particularly late in games.

"They shouldn't be allowed to (wait). Once it's packed and there, they shouldn't be able to wait 35 seconds. That's not the rule. Get the scrum packed and let's get on with the game. It's not mandatory that you have to have 35 seconds," Bennett said.

Bennett is right. It's not mandatory. But it is legal for players to take up all of the time available to be there and pack any scrum.

"They won't take advantage if we police the rule properly, the interpretation of the rule. The rule says in 35 seconds you have to have that scrum packed. Nobody says you have to wait 35 seconds before you can pack the scrum," Bennett said.

"It was ridiculous. As Cam said, I was sitting there watching and thinking ' this is not what we want'. We're all sitting around waiting for the clock to come down. That's not what the rule was for."

Shot clocks have always been a double-edged sword. They were introduced in basketball to speed up the game, the same as is desired in league, but teams regularly use them to eat up the clock towards the death.

That could well be the side-affect of the new clocks introduced in rugby league.

"At one stage I think they waited 20 seconds," said Indigenous All Stars coach Laurie Daley. "It was frustrating. I don't know what the answer is."