The flag is officially described by the council as:[2]A black cross on a gold background, with the badge (a dolphin Naiant on a sail) in the centre.

The colours are a yellow background, a black cross, and a blue badge and the proportions of the flag are 9 ft x 6 ft.The badge depicted in the centre of the flag was granted to Wellington City Council by the College of Arms in 1963, with the heraldic description: A Roundel Azure thereon a Lymphad Or the sail argent charged with a Dolphin naiant Azure pennon and flags flying Argent each charged with a Cross Gules.

[3]The idea of Wellington having its own flag was brought up by councillor John Gibbs Churchill in April 1957, which was later approved by the council on 15 May 1957.

A design made by Dennis Beytagh, with two silver ferns, a shield, and the letter 'W' for Wellington won the competition and the creator was given £25 in prize money.

[1] The flag has been criticised by many, including the former deputy mayor, Jill Day and broadcaster Keith Quinn for symbolising colonialism by having a boat and three Saint George's Crosses.