A woman was allegedly assaulted with a machete by a teenager in a store in Greenway on Monday night.

Police say that four teens got into a verbal altercation with a woman at the BIG W at the SouthPoint shopping centre at about 6pm. One of the teens allegedly produced a machete and struck the woman on the arm with it, causing bruising.

The teens fled but police subsequently detained a 14-year-old boy, who will be summonsed to appear in court at a later date, charged with possessing a knife in a public place (not the machete).

Two other teens from the group were located outside the centre.

Police want to identify the fourth teen ,who police believe struck the woman with the machete. He has dark hair and was wearing a dark hoodie and grey trackpants.

Anyone who can assist police is urged to contact them via the Crime Stoppers ACT website.