It commemorates Henry Greathead Rex Mason (1885-1975), one of New Zealand's longest-serving MPs. After completing an LLB at Victoria University College, Mr Mason became a lawyer in Pukekohe. He began a long career as an MP when he was elected to Parliament in 1926.

When he retired in 1966 he had been Attorney-General and Minister of Justice in the first Labour Government and also in the second Labour Government, from 1957 to 1960. He was the driving force behind the Crimes Act 1961 and was awarded an honorary LLD by Victoria University.

The prize – which is valued at around $1,000 each year – is managed by the Wellington branch of the New Zealand Law Society, as trustee for the Honourable Rex Mason Trust. Under the terms of the trust, the judges are a nominee of the Chief Justice, the Dean of Victoria University of Wellington Law School, and the Editor of the New Zealand Law Journal.

The judges are required to be guided by a number of factors. These are: the educational value of each article, its literary value, its ability to stimulate awareness in young lawyers of the nature and function of law as seen in and derived from personal experience, the extent to which it draws attention to the need for development of law in times of social change, and the extent to which each article stimulates the interest of practising members of the legal profession.

To enter for The Honourable Rex Mason Prize 2023, fill out the official entry form.

Prize winners since 2010 are as follows: