"Internationally and in New Zealand there is a huge appetite amongst investors for generally green and sustainable investment options", he said.
Bonds are a simple fixed-income investment people can understand, he said.
"You issue the bond, people buy it, and then you pay it back over the period of the bond."
Nash suggested the green bond be jointly issued by Wellington City Council and Greater Wellington, although how to do that still needed to be worked through.
The idea comes at a time when both councils are facing the question of how to fund Let's Get Wellington Moving.
The Government will foot 60 per cent of the bill for the $6.4 billion transport project, while local government is set to contribute 40 per cent.
"It's an attractive option to have a way of financing this critical infrastructure like LGWM now, whilst not just putting the burden on to Wellingtonians and people in this region who are paying rates today, but sharing it across generations", Nash said
Sitting Green city councillor Iona Pannett said she was worried the council did not have enough money to fund all the infrastructure it needed to move to a zero carbon community and economy.
"So we need to raise some cash and a lot of it because we can't just keep going to the rate payer."
Housing New Zealand recently issued $500m of a new 7.5-year Sustainability Bond.
"The proceeds raised from the Sustainability Bond issue are earmarked for expenditure that has positive environmental and social outcomes, including building homes that meet certain green criteria as well as homes that incorporate mobility and accessibility considerations into their design," HNZ Board chairwoman Adrienne Young-Cooper said.
The bond was issued on March 28, 2019 at a yield of 2.247 per cent and lifted HNZ's total market debt to $1.45 billion.
Last year Auckland Council labelled its green bond a success after raising $200m to pay for electric trains and associated infrastructure.
Auckland Council chief sustainability officer John Mauro said it reflected the growing global interest in green finance.
"Meeting demand through further domestic green bond issuances and other climate finance mechanisms will be critical to transitioning New Zealand and Auckland to a net zero emissions economy."
The Greens candidates are also campaigning on light rail, a package for bus drivers to improve pay and conditions and building green roofs.
Green Wellington candidates are:
Laurie Foon, Wellington City Council, Southern Ward
Thomas Nash, Greater Wellington Regional Council, Wellington constituency
Richard McIntosh, Wellington City Council, Onslow-Western Ward
Iona Pannett, Wellington City Council, Lambton Ward
Sarah Free, Wellington City Council, Eastern Ward
Sue Kedgley, Capital and Coast District Health Board.
