Piers Abbenes has built an art collection that could take a lifetime to amass.
The painting by an English artist has been held in private collections and rarely seen by the public before.
"I just thought it was utterly bizarre for someone to know so little about the arts and to have asked for the portfolio."
Sir Vincent excelled as a novelist, playwright and poet, becoming New Zealand's ninth poet laureate in 2013.
The award has been likened to winning gold at the Olympics.
Legally he can't tell the museum what to do.
The renowned street artist's latest work has sparked interest and excitement across social media platforms.
Jason Smith of Kauri Museum argues access to museum's treasures is "a basic human need".
A campaign, Keep the Lights On, comes amid rising costs and dwindling funding.