Police are seeking witnesses to an incident that occurred outside a CBD night club last month.

At around 3am on Saturday November 30, patrons made their way out of the Grafton Street complex at the close of trading.

See video of the incident below:

While patrons were gathering on the footpath area at the front of the establishment, a small incendiary device believed to be a firework, was thrown or dropped among a group of patrons.

The firework detonated and resulted in a burn injury to a 19-year-old woman. A 29-year-old man sustained contusions and burns to his torso and damaged his shirt. The incident was subsequently reported later the same day.

Detectives have spoken with multiple witnesses, however, they believe there may be others who either witnessed the incident or may have been struck by the firework and not yet made a report to police.

Anyone with information is urged to make contact via Policelink on 131444.