A NSW couple who went missing with their three-month-old son have been arrested in Queensland after being involved in a car crash.

A NSW couple who sparked a police search when they disappeared with their three-month-old son have been arrested.

Police issued a call for urgent public assistance in the early hours of Tuesday after family reported the couple missing from their home in Lake Macquarie, south of Newcastle.

Police said at the time they held “serious concerns” for the baby due to reports of erratic behaviour from his parents.

Queensland officers found the family after they were allegedly involved in a car crash in Warwick, in the southeast of the state.

The 32-year-old man and a 20-year-old woman have been arrested and are being questioned by police, while the boy was taken to Warwick Hospital for observation.