The six o'clock swill was an Australian and New Zealand slang term for the last-minute rush to buy drinks at a hotel bar before it closed. During a significant part of the 20th century, most Australian and New Zealand hotels shut their public bars at 6 pm. A culture developed of heavy drinking during the time between finishing work at 5 pm and the mandatory closing only an hour later.
Six o'clock closing was introduced during the First World War, partly as an attempt to improve public morality and partly as a war austerity measure. Before this reform, most hotels and public houses in Australia had closed at 11 or 11:30 pm. Support for changing hotel closing times originally came from the temperance movement, which hoped that implementing restrictions on the sale of alcohol would lead eventually to its total prohibition. Although the movement had been active since the 1870s, it had been gaining ground since the 1900s following the introduction of 6 o'clock retail trade closing, first legislated in Western Australia in 1897. The argument made by the temperance movement challenged the grounds for public houses being "kept open while bakers' shops were shut". Prominent groups in this movement were the Woman's Christian Temperance Union and the Rechabites. Their agitation was augmented with the outbreak of war in 1914 where it was argued that a "well-ordered, self-disciplined and morally upright home front was a precondition for the successful prosecution of the war."