Former All Black teammates Tana Umaga and Luke McAlister will square off tomorrow in a provincial contest with international repercussions.

All Black coach Graham Henry will travel to Pukekohe to study that duel and others who are fringe contenders for the end-of-year tour.

While North Harbour and Counties Manukau fans will urge their teams on in the quest for a top-seven finish in the ITM Cup, the young bull-old bull battle in midfield should be captivating.

McAlister and Umaga started alongside each other once in black when McAlister made his debut against the Lions in 2005.

Not long after Umaga retired while McAlister struggled with injury.

Tomorrow's match is a rare back-up for Umaga after his prominent display against Northland while McAlister has been cleared after fears he had broken his jaw last week.

"Tana is in great nick, he has trained well and we make sure we manage him," Counties coach Milton Haig said.

Umaga's experience and decision-making had made a significant impact on the squad.

He shared his knowledge, he was humble and the team had thrived with his input.

"Tana is also a very important part of our backline where he reads the game well and shows with his defence how much he is a competitor," said Haig.

If McAlister gets some strong possession and his dancing feet moving, the midfield duel should be a compelling part of what looms as an entertaining package.

"Luke has been good for us this year and this will be his 50th game for Harbour too," said Harbour coach Craig Dowd.

"He took a bang on the jaw but the swelling went down quickly and he is feeling much better now."

Harbour have lost flanker Malakai Ravulo to a family funeral, meaning a rejig in the loose forwards with Tom Chamberlain switching to openside and Richard Mayhew coming in on the blind.

Captain Mike Reid returns at loosehead prop after a foot injury and his fellow frontrower Ben Afeaki at tighthead after illness.

Dowd said his side were on strong alert for the Umaga danger and would be punished if they did not shore up their defence.

Harbour had leaked too many tries.

There were four against Manawatu last week, though one was from a long-range turnover and another an intercept.

They were on defence for 60 per cent of the game and Dowd felt their structure was much improved. They also needed to be more aggressive at the breakdowns.

"Once upon a time you would say Counties backs were strong so you would take them on in the forwards," said Dowd. "However, this year they have proved to have a strong pack and are not afraid to play it up the middle."

The suspended Fritz Lee and Commonwealth Games-tied George Stowers would be losses but Counties had shown their depth this season.

"We made it very clear we needed to win three on the bounce and that job is only two thirds done - this remains a must-win game for us," Dowd said.

"The boys are getting sick of me saying this is the biggest game of the year but it is. At times we have gone well and last week we were happy to win but it was not a great win.

"We know there is another level we can get to."