Heinrich Arnold Nordmeyer (1901 - 1989), often later known as Arnold Henry Nordmeyer, was a New Zealand politician. He was leader of the Labour Party for three years while it was in Opposition.

Nordmeyer was born on 7 February 1901 in Dunedin, New Zealand. His father was a German immigrant, while his mother was from Ireland. He was educated at the University of Otago, studying social science. After graduating, he studied theology, having always been highly religious. In 1925, he received his ordination as a Presbyterian minister, and was appointed to a position in the small town of Kurow.

While in Kurow, he came into contact with Jerry Skinner , a trade union official involved with construction of a hydroelectric dam on the Waitaki River. Nordmeyer became highly interested in the welfare of the workers on this project, and consequently became interested in left-wing politics.

Shortly before the 1935 elections, Nordmeyer stepped down from his church position, stating an intent to contest the Oamaru seat for the Labour Party. In the election, Nordmeyer was elected. The 1935 election itself was a huge victory for Labour, and the party's leader, Michael Joseph Savage, became the country's first Labour Prime Minister.

In Parliament, Nordmeyer proved to be a skilled debater, but also had a somewhat troubled relationship with his party's leadership. Nordmeyer became part the faction led by John A. Lee, who criticised Savage's policies as too moderate. Gradually, however, Nordmeyer became disillusioned with Lee, alleging that Lee was egotistical and self-important. Nordmeyer later co-operated with more moderate politicians such as Walter Nash in drafting the party's social security policies.

After the 1938 elections, which Labour won resoundingly, tensions between the moderate and extreme wings of the party became worse. Nordmeyer attempted to take a position between both groups, but was generally closer to Lee's camp than to the other. 1940 saw both the death of Savage, but also saw the expulsion from the Labour Party of Lee (a move which Nordmeyer opposed, although not strongly). Nordmeyer nominated Gervan McMillan , an old friend from Kurow and a supporter of Lee, as the party's new leader. McMillan, however, was defeated by Peter Fraser, Savage's chief lieutenant.

In 1941, Nordmeyer became Minister of Health. In this role, he was responsible (along with Walter Nash) for introducing state subsidies for doctor's visits. In 1947, Nordmeyer became Minister of Industries and Commerce, and came to be regarded as one of the most senior members of the government.

In the 1949 elections, however, Labour was defeated by the National Party under Sidney Holland. Nordmeyer himself lost his seat of Oamaru. In 1950, however, Peter Fraser died, and Nordmeyer was elected as his replacement in the seat of Brooklyn.

In the short period between Fraser's death and Nordmeyer's return to Parliament, Walter Nash had been hastily elected leader of the Labour Party. The speed of Nash's ascent is sometimes seen as evidence that his supporters considered Nordmeyer a threat. Nordmeyer, although he had worked with Nash before, opposed Nash's elevation, having considerable objections to Nash's leadership style - Nordmeyer considered Nash to be both autocratic and uninspiring. In 1954, Nordmeyer began a challenge for the leadership. Although Nordmeyer gained considerable backing from certain sectors of the party, Nash enjoyed strong union support, and defeated the challenge in caucus on 23 June.

When Labour won the 1957 elections, Nordmeyer was made Minister of Finance, and was ranked third within the government. A short time after taking office, Nordmeyer reached the conclusion that the country was on the brink of a balance of payments crisis, and decided to take strong measures in response. His first Budget (sometimes labeled "the Black Budget") introduced a number of unpopular changes, including significant tax increases. The particularly large tax increases for alcohol and tobacco, coupled with Nordmeyer's strong religious background, also created the impression that he was trying to impose puritan-like social reforms. Labour was voted out of office in the 1960 elections, something that many historians blame on Nordmeyer's "Black Budget".

Despite attracting considerable blame for Labour's loss of support, Nordmeyer was elected to lead the Labour Party when Nash retired in 1963. The memory of the "Black Budget" still haunted Nordmeyer's profile, however, and many within the party believed that it was time for "a new generation" to take control. Norman Kirk eventually emerged as the favourite candidate to succeed Nordmeyer, and in a vote on 9 December 1965, Nordmeyer was defeated by 25 votes to 10.

Nordmeyer remained in Parliament for another four years, retiring at the 1969 elections. He later held a number of roles in government, including a time as a director of the Reserve Bank of New Zealand. In 1987, he was made a founding member of the Order of New Zealand.

Nordmeyer died in Wellington on 2 February 1989. He was survived by his wife, Frances Maria Kernahan, whom he had married in Oamaru on 28 October 1931. The couple had two children.