The PSNI stated the siblings, aged between 16 and eight, could also be with their dad and mom Kathleen and Martin Maughan, and should have travelled to the Republic of Eire.
The lacking youngsters are Louise, 16, Marie Theresa, 15, Owen, 12, and Christina, eight.
They had been reported lacking from the County Fermanagh city of Lisnaskea on October 5.
Chief Inspector Lynne Corbett issued an enchantment to the general public on Sunday night to assist them find the youngsters.
She stated: “We’re asking that Kathleen or Martin, the youngsters, or anybody who is aware of of their whereabouts, get in contact with police and tell us the place the youngsters are and that they’re secure.
“I’d additionally ask that they be returned to Northern Eire as quickly as doable. Police might be contacted by calling 101, quoting reference 1181 05/10/23.”