Labour received a hefty pre-election Christmas present last year, with a life-long member leaving the party the largest political donation of 2019 in her will.

Labour was bequeathed just over $205,000 by the estate of Auckland resident Barbara Holt in late November, the official register of major donations shows.

Holt, who grew up and lived in the Labour stronghold electorate of Mount Albert, died in July last year.

Her family were heavily involved with Labour, her parents becoming active members in the Mount Albert branch in 1938 and her father, Laurence, seeking an electoral seat to stand in that year.

According to her letters to friends, Barbara Holt, born in the late 1930s, served as a senior executive officer on numerous advisory boards to the Department of Social Welfare. She was awarded a Suffrage Centennial Medal – in recognition of services for women - in 1993.

In later life she was involved in the Mount Albert Historical Society and a co-ordinator for Breast Cancer Action Aotearoa in the 1990s. She was the sister of historian and professor Jim Holt.

Holt and her siblings were well-known figures among Auckland's Labour members, with former Prime Minister Helen Clark saying she knew the family and their involvement in the party.

Carron Boswell, a friend of Holt's and fellow historical society member, described her as a "passionate, intense and singular" figure.

"She had a huge amount of passion," Boswell said.

"She really wanted our local history to be a history of everyone, not just local, landed families and rich people."

Historian Michael Bassett, who wrote friend Jim Holt's obituary in 1983, said the bequest did not surprise him.

"Her family was always Labour," he said.

However, Bassett, Clark, Clark's former electoral secretary Joan Caulfield, and other contemporaries said while they knew Holt's brothers, they did not know much more about Holt herself.

Labour General Secretary Andre Anderson, declined to comment, saying it could not discuss donors or donations for privacy reasons, as did Prime Minister Jacinda Ardern.

The donation was the single largest declared by any party in 2019, the second largest being $110,000 given to ACT by property developer Christopher Reeve.

It is also the largest Labour has received since it was gifted $430,000 in 2013.

Holt isn't Labour's largest donor in recent years, though, with retired High Court judge Robert Smellie, QC, donating a total $335,000 since 2017, including $140,000 in 2019.

The Green Party last year received a $350,000 donation, the largest of any party in almost a decade, which also passed on through a will.