A rare show by comedy duo Flight of the Conchords raised around $70,000 for Masterton's Makoura College, the former high school of band member Jemaine Clement, at a fundraiser last night.

The 2000 tickets, priced at $40, were intended to go on sale for Wairarapa residents a day before being opened to the wider public, but sold out in 91 minutes.

Clement contacted his old teacher Rae McKenzie last year after hearing the struggling school's falling roll - from 600 to 200 - may force it to close, asking if there was anything he could do to help.

He attended Makoura College in the 1980s while living in a state house in Masterton with his mother and two brothers.

"I was worried about it. I really enjoyed my time at this school," he told Radio New Zealand.

He emailed Mrs McKenzie again in mid-March to say he and sidekick Bret McKenzie would be available to play at the school on March 31.

Clement said he was amazed how big the duo was in Masterton.

"We're huge in Masterton. I'm wondering if this might have spread as far as Carterton, and possibly even to Featherston."

He said it was an honour to play a venue where, as a child, he was taken to watch the Golden Shears shearing competition.

Principal Tom Hullena said the concert was extremely successful, and had raised around $70,000-$75,000, including fundraising by cultural groups who sold snacks and t-shirts at the event.

An auction of an acoustic guitar signed by McKenzie and Clement was won by multi-millionaire businessman Gareth Morgan for $6000.

He said a committee would be set up to decide how the money would be spent, but it was likely it would go towards performing arts, and possibly a music scholarship.

Students, such as one currently commuting to the Wellington-based New Zealand School of Music, had a lot of talent, but were constrained by costs.

The concert was one of few in New Zealand in recent years by the duo, who have a huge following and TV show in the US.

It followed a show earlier in the day just for Makoura College students.

Ticket scalpers who were attempting to sell the $40 tickets for triple their original price received flak on Trade Me, with potential buyers asking if the profit would also be donated to the school.

Mrs McKenzie had contacted one seller and persuaded them to withdraw the sale, saying it was unfortunate that people were trying to make money off the charity event.

"The price was kept low to make sure locals would be able to go ... it wasn't kept low for some people to make money on," she told the Wairarapa Times-Age.

Flight of the Conchords leave for a two-month tour of the United States on Friday.