Mr Osborne said the review of Te Ahu started while he was still managing the council-owned, trust-run centre.
The review's aim was to clarify and upgrade the relationship between the council and the trust, he said.
"It's a good thing and it will help decide who does what going forward."
Te Ahu cost $14.8 million to build - a combination of ratepayer funding, grants and fundraising - plus another $700,000 in operating costs over the past two years.
In a story earlier this week, NBR Online said its enquiries since March 10 about the review and Mr Osborne's role at Te Ahu had been passed to National Party communications manager Clark Hennessy, who would not allow the candidate to be interviewed ahead of the byelection.
The Far North District Council is reviewing the governance and funding of Te Ahu and Kerikeri's Turner Centre. In both cases, it wants greater transparency and a service contract with measurable outcomes in exchange for ongoing ratepayer support.
Mr Osborne managed Te Ahu before he was appointed council asset manager about six months ago.
The facility opened in April 2012 and combines council offices, a library, museum, i-Site, cinema/theatre, cafe, community hall and exhibition areas.
According to council reports, Te Ahu cost $185,000 to run in the 2012-13 financial year and $523,000 in 2013-14.
In that year, its operating income was $35,000.
Vote for Peters, urges rival candidate
Home-grown political party Focus NZ is calling on its supporters to cast their votes for NZ First's Winston Peters in tomorrow's Northland by-election.
The call comes after Labour leader Andrew Little gave his party's supporters the green light to back Mr Peters.
Focus NZ candidate Joe Carr used a front-page advertisement in the Northland Age yesterday to urge Northlanders to vote not for him but his NZ First rival. That was the most effective way of sending the National-led Government a message, he said.
Focus NZ has campaigned mainly on roads and Government policies it says hurt provincial New Zealand.
Mr Carr disputes figures cited by National for its spend on Northland roads since being elected.
The Government has put the figure at $750 million but Mr Carr said it was $705 million, with $185 million of that from local ratepayers. Auckland received $755 per person per year in road funding while the equivalent figure for Northland was $538, he said.
In last year's general election Focus NZ won 1661 Northland electorate votes.
The full list of candidates is: Adrian Bonner (Independent), Mr Carr (Focus), Robin Grieve (Act Party), Maki Herbert (Aotearoa Legalise Cannabis Party), Adam Holland (Independent), Mr Osborne (National), Rob Painting (Climate Party), Mr Peters (New Zealand First Party), Rueben Taipari Porter (Mana Movement), Willow-Jean Prime (Labour Party) and Bruce Rogan (Independent).