Witcombe, who is Northland's ITM Cup coach, says the match is an incredible opportunity for the Northland team and the public.
"I think it's really exciting for the players, they're going to get a good feeling of what's required at international level," he said.
"We're pretty excited for the boys."
Witcombe added he didn't think the match would be a case of leading lambs to the slaughter, saying his side is yet to have a loss blow-out.
He said his side would go in with a specific purpose and take away what they could.
"We're going to focus on what we're going in for, if we can hold together our structures and our game plan against them in a reasonable shape I'll be happy.
"We've got them in the second 40 so hopefully they'll be a bit tired by then," Witcombe joked, adding the match would serve as perfect preparation ahead of the ITM Cup which starts the weekend after.
"There hasn't been a blow-out yet, so I'm sure our boys will step up and make sure there isn't one."
Northland Rugby Union (NRU) chief executive Jeremy Parkinson said he was glad North Harbour boss Brett Hollister had kept the Taniwha in mind.
Parkinson said the match had only come about because North Harbour had lived up to their end of an agreement which would see the two sides play each other in pre-season.
The match won't be a first - the last time Northland played the All Blacks would have been in the 1970s when the national team did a domestic tour.
All Blacks coach Steve Hansen said the matches were "win-win" from where he sat ... his side gets some training matches and so do North Harbour and Northland.
Tickets for the All Blacks match are available via the Harbour Rugby website from Tuesday. Adult stand tickets are $15. Children are $5.
Also, in case you weren't aware, a Northland Barbarians side will take on the Blues at Toll Stadium in two weeks. Tickets are available from the NRU office.