Police and family are appealing for public help as welfare concerns rise for two young children who were last seen at a Waterloo unit complex around midday on Sunday.

The missing children are five-year-old Normani Murray-Lawrence and two-year-old Laphius Murray-Lawrence, described as Aboriginal or Torres Strait Islander, with Normani about 105 cm tall in a pink dress and white sandals and Laphius about 85 cm tall in a navy jumper and shorts, both last seen in the Waterloo area.

Authorities believe the trio may be travelling in a white 2013 Nissan Navara dual cab with NSW plates DH13TM, seen in Waterloo and Redfern, and may be with the children.

At least one 35-year-old Aboriginal or Torres Strait Islander man, around 165 cm tall with a slim build, was last seen with the children, wearing grey track pants or tracksuit pants, a red/black polo shirt, a white jacket, black shoes, and carrying a black backpack.

The children are also believed to be in the company of a 24-year-old Aboriginal or Torres Strait Islander woman, about 160 cm tall with long brown hair and a leg injury, described as wearing a black hooded jumper, red T-shirt, black leggings, a black cap, and barefoot or with an injured leg.

The last confirmed sighting places the children around 12:00 in a unit complex on Pitt Street in Waterloo.

Authorities stress this is an urgent welfare concern and are urging the public to provide information to South Sydney Police or Crime Stoppers at 1800 333 000 or online, with all tips kept confidential.

Public assistance is requested; anyone with information should contact South Sydney Police or Crime Stoppers immediately.

Additional details describe Normani and Laphius’s appearance and how they were last seen: Normani with pink dress and white sandals, Laphius barefoot in a stroller.

The welfare search is ongoing and authorities are coordinating efforts as they appeal for information from the public.

Police and family are openly seeking public assistance to locate the children and ensure their safety.

Multiple reports describe the 35-year-old man in similar terms across notices, reinforcing the need to identify him and locate the group.