The largest donation was from the Engineering, Printing and Manufacturing Union which gave $40,000, according to the disclosure to the Electoral Commission.
However, that donation was $20,000 less than in 2008 and the lowest the union has given since 1999 - a drop its national secretary Bill Newson said was because of its falling membership in economic hard times when many workers in the manufacturing sectors were hit with redundancies and job losses.
Extra costs such as representation at the Pike River royal commission also affected the union's ability to donate.
Department of Labour records show that between 2008 and 2011, the EPMU's membership shrank by 7000 - a 16 per cent drop from 44,808 to 37,808.
Mr Newson said the donation size was not related to Labour's chances of winning the election or out of dissatisfaction with its policies, which he described as "quite gutsy."
The EPMU's donation was disclosed under electoral laws which require prompt disclosure of donations of more than $30,000. The other union donations will not be officially disclosed until parties file their election returns in March. However, the other unions volunteered the information when asked by the Herald.
Some were down - the Meat Workers' Union gave $18,000, $7500 less than in 2008, and the Service and Food Workers' Union gave $15,000, down $5000 from 2008.
SFWU John Ryall said his union now focused more on running its own campaigns on election issues rather than simply giving money to parties, including opposing National's changes to employment laws.
The slack was picked up by larger donations from MUNZ and the Dairy Workers' Union which donated $25,000 - $13,000 more than in 2008. The FIRST union (a merger of the old National Distribution Union and Finsec) also donated $4000 each to Labour, the Green Party and the Mana Party. It is not an affiliate of Labour, but has sometimes donated to it, including $24,000 in 2005.
Labour received only two donations of more than $30,000 in 2011 - the EPMU donation and $50,000 from the Todd Corporation, which gave the same amount to National.
By comparison, National received eight, totalling $490,938, mostly from corporates.
The most recently disclosed was $86,005 from the Gallagher Group, an agriculture company based in Hamilton.
Labour general secretary Chris Flatt said the low number of large donations was not a reflection of the party's fundraising effort, which had met its targets.
"We've always had a number of smaller donations from individuals and groups. That continued last year."
WHAT THEY GAVE
(2008 donation in brackets)
* Engineering, Printing and Manufacturing Union: $40,000 (2008: $60,000)
* Dairy Workers' Union: $25,000 (2008: $12,000)
* Maritime Union: $18,500 (2008: none disclosed)
* Meat Workers' Union: $18,000 (2008: $25,500)
* Service and Food Workers' Union: $15,000 (2008: $20,000)
* FIRST Union (not affiliated): $4000 (2008: nil)