The Green's general-secretary Gwen Shaw said the party was very grateful for Harris' donation.
She had been a party member since 1999.
"She was a lovely woman; never made a fuss but just got on with whatever she thought she could do to improve the world."
Harris lived in East Auckland and was an active supporter of her local branch, particularly when she was younger, Shaw said.
"In recent years she lived in a retirement village but continued to support our work by her advocacy and regular financial commitment. She left a one-fifth portion of her estate to the Green Party."
Other benefactors of Harris' will were the Fred Hollows Foundation, Forest & Bird, SAFE, and Amnesty.
Harris was a widow and had no children.
Any donation which exceeded $30,000 is required to be filed to the Electoral Commission to be made public within 10 working days of being made.
The last time the Greens received a donation of this size was in August of 2016 when the party received more than $280,000 from the estate of Elizabeth Riddoch.
At the time, the Herald reported she was not a party member and did not have any formal connections to the Green Party.
But Harris' donation does not come close to the $2.7 million given to the Internet Party by Kim Dotcom in 2014.
In 2012, then Conservative Party leader Colin Craig donated $1.6m to his own party.
Between October 2013 and the end of last year, the former The Opportunities Party leader Gareth Morgan donated $2.2m to his party.
In October, Green Co-Leader Marama Davidson called for reform of the political donations regime, after it was revealed the National Party had received more than $3.5m in anonymous donations in 2017.
She said it was impossible to know who was influencing New Zealand's politicians and Parliament was "ripe for influence by big corporations, and potentially corruption".
The Greens have called for other changes too, including capping individual donations at $35,000, banning overseas donations and increasing taxpayer funding for campaigning.
Justice Minister Andrew Little is in the process of deciding if changes to the way political parties are funded need to be put to a referendum next election.
Major political donations made in 2017 and 2018:
Greens – $350,000 from the Estate of Betty Harris (December, 2018)
ACT – $61,000 from Dame Jenny Gibbs (August, 2018)
TOP – $430,000 from Gareth Morgan (November, 2017)
Māori Party – $43,000 from Tukuroirangi Morgan (October, 2017)
Labour – $100,000 from the NZ Dairy Workers Union (September, 2017)
National – $112,000 from Alpha Laboratories (August, 2017)
TOP – $500,000 from Gareth Morgan (June, 2017)