Police believe the family, who are from the Republic of Ireland, are currently living in the Ballymartin area.
John Kelly, Melissa Teague and their six children, aged between five years and nine months old and originally from the Longford area, were last seen in the Ballymartin area on Wednesday, 7 January.
Detective Chief Inspector Stephen Wright said: “We are keen to make contact with the family and I am asking John or Melissa to phone us on the 101 number.
“I would also like to hear from anyone who has knowledge of the family’s whereabouts or who may have noticed a family of two adults and six children in the local area or further afield.
“We can be contacted in Banbridge on the 101 number.”