Siblings, Karly and James Lowe, aged 13 and eight respectively, were last seen outside their home on Antares Close about 6.20pm on Wednesday.

When they failed to return home, officers from South Coast Police District were notified and despite extensive inquiries, have been unable to locate them and are now appealing for public assistance.

Police and family have concerns for the welfare of Karly and James due to their young age.

They are believed to be together and may have travelled to Kiama and possibly onto Sydney using the railway network on Thursday, however, may have since returned to the Nowra area.

Karly is described as being of Caucasian appearance, about 170cm tall, of slim build, with long, light brown/blonde hair. She was last seen wearing a red 'Champion' hooded jumper and black football shorts with 'Waminda' written on the leg.

James is described as being of Caucasian appearance, about 140cm tall, of slim build, with a shaved head and a long strawberry blonde/red fringe.

He was last seen wearing an oversized black hooded jumper over his school uniform including a dark coloured polo shirt and shorts, a faded blue 'Adidas' cap (as depicted) and white Adidas sneakers. He was carrying a black and rainbow coloured scooter.

Police are urging anyone with information about their whereabouts to contact Crime Stoppers on 1800 333 000.