But leading Australian cricketer Andrew Symonds has blasted the move, calling it "un-Australian", while Victorian cricket boss Tony Dodemaide admits eligibility rules need to be tightened.
New Zealand wicketkeeper and hard-hitting one-day opening batsman McCullum has agreed to play for New South Wales against Victoria in the final of the Australian domestic twenty/20 competition in Sydney tomorrow night.
By playing in the match in Sydney, McCullum will guarantee his presence in the rich Champions League in India in October.
Otago Cricket chief executive Ross Dykes said the offer would not have been considered if there was more at stake in the match in Invercargill on Sunday against Wellington.
"If there was a semifinal riding on the match then there was no way this offer would have been considered," Dykes said.
"This is a one-off, created by circumstances which might never be repeated again.
"I've always been a cricket traditionalist and this just feels right.
It is first and foremost a cricket decision and not a commercial decision."
Otago has already assured itself of a semifinal in the State Shield, the one-day competition, but needs to win on Sunday to guarantee a home semifinal.
Dykes said McCullum was unavailable to play the semifinal and final of the State Shield, as he would be in Australia with the Black Caps, so it made sense to bring someone else in to get him used to the competition.
Otago would not be paid any money by New South Wales, although he hoped the Australians recognised the favour Otago was doing.
Australian teams were able to use one overseas player per team.
"This deal is very advantageous for Otago cricket, increasing Otago's profile."
Dykes said McCullum's playing cricket in the rich Indian Premier League was good for cricket as it raised the profile in the game in New Zealand.
"Brendon has done a lot for Otago cricket since coming back here.
Sponsorship this year has increased by about 50% and though that is not all entirely down to Brendon, he contributed to it."
He said McCullum's dedication to the Otago team could be showed by his decision to catch a 6am flight from Napier last week to get to Dunedin to play for Otago against Canterbury.
Otago coach Mike Hesson was perfectly happy with the situation.
He said Otago had to win a semifinal and a final without McCullum, as he would be playing for New Zealand against Australia, so it made sense to get someone else to play on Sunday.
He said the team had won plenty of games without McCullum.
New Zealand Cricket chief executive Justin Vaughan said there was much potential up-side to having McCullum having a guaranteed spot in the Indian League.
Symonds told AAP yesterday he could not understand what New South Wales was trying to do and it went against the spirit of being Australian.
He said it was unfair a young Australian player would be forced to miss out for McCullum.
Cricket Victoria chief executive Dodemaide said it was unusual there was not a qualification period to be eligible to play in the final.
But as the competition was growing, into its fourth year, the rules were evolving with it.
"Maybe the competition squads have to be settled by a certain time so no new players can be brought in," Dodemaide told the Otago Daily Times from Melbourne.
"Certainly the prize money's significance brings a whole new dimension to the game."
