What was once a form of New Zealand legal tender, and quickly became something forgotten about under the couch, has found a new lease of life in the United States.

When John Green - an American author, vlogger, writer, producer, actor and editor - tweeted his need for some "nickels", what he meant was the disestablished Kiwi five-cent coin, and what he needed was hundreds of them.

What he got was 8000 five-cent coins, thanks to an Auckland school teacher who collected them, flew to America with them in a suitcase, and then shipped them to Green's address at a cost of $500.

MEGAN DAVIDSON/SUPPLIED Auckland librarian and teacher collected 8000 disestablished Kiwi five-cent coins to send to American author, John Green.

Green's call for five-cent coins has ties to his new book, Turtles All the Way Down, which features a tuatara.

Somewhat unusual question: Anyone in New Zealand have access to a very large quantity of nickels? I'm in the market for some. — John Green 🐢 (@johngreen) September 15, 2017

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NIGEL MALTHUS/STUFF Auckland librarian and teacher collected 8000 disestablished Kiwi five-cent coins to send to American author, John Green.

While researching the endemic species to New Zealand, he discovered ours was the only country that minted coins featuring an image of the reptile.

He wanted to give the coins to people during his book tour, and later as token of kindness, as the book touches on mental wellbeing.

But since five-cent coins were taken of circulation in 2006, the American could only find 23 of them on Ebay for US$22 (NZ$32).

Megan Davidson, a librarian at Westlake Girls' High School in Auckland, saw the tweet and thought it would be "a fun idea to collect the coins and get them to him".

She asked friends, colleagues and even wrote to the newspaper about wanting to collect the cupronickel, at 19.43 millimetres in diameter and weighing 2.83 grams.

They arrived in their droves. People from all over the country sent in their old coins - one man delivered 1500 in one bag.

"What was sweet was, most of the coins came with notes. They were glad that the coins finally had a use, even if they didn't know what for," Davidson said.

"There was one from a man in Whangarei, which said things in te reo Māori about how sacred the tuatara is and finished with kia kaha."

Amid one of the more stressful/scared/overwhelming periods of my life, people in New Zealand have been incredibly, irrationally kind to me. — John Green 🐢 (@johngreen) September 29, 2017

During the school holidays, Davidson and her husband flew to her old home town near Seattle in the US state of Washington with the coins in a suitcase that weighted just over 22kgs.

She then mailed them to Green's address in Indianapolis at a cost of $500, and was reimbursed.

What came next brought her to tears. Green dedicated one of his thousands of vlogs on YouTube to the coin, Davidson, and the Kiwis who donated them.

"I will try to use them well; to give them out over the course of my life to those who might need a physical reminder of how kind people can be," he said.

"To the Kiwis that made this happen, thank you. I know you will say it is just a little thing, but little things matter."