Daniella D'Addario, 35, and Josaia (Joey) Vosikata, 27, were reported missing on Monday after Ms D'Addario's concerned family members could not contact her over the weekend.

ACT Policing detective Acting Sergeant Jason Taylor said police didn't believe there was any foul play involved in the pair's disappearance.

"We're concerned for their welfare and safety as the circumstances under which they went missing are very uncharacteristic of them both."

He said it was very common for both to be in regular contact with their families, who hadn't heard from either since Sunday.

The pair were believed to have travelled to the Casuarina Sands area on Sunday before heading to the south coast.

Police said the couple could be in the Bermagui area and travelling in Ms D'Addario's silver or light blue Hyundai Getz, with ACT registration YEF19M.

"We're appealing for anybody who may have seen this vehicle or if they do see it to contact police immediately on 131 444."

ACT Policing initially described the pair as a couple, but detective Acting Sergeant Taylor later wouldn't comment on the nature of their relationship except to say they knew each other.

Detective Acting Sergeant Taylor said officers were liaising with NSW Police and were in constant contact with family members in Canberra.

"There is no indication of any foul play or any malfeasance that has occurred," detective Acting Sergeant Taylor said at a press conference on Wednesday.

"We are here to ask Joey, to ask Daniella, to come forward to police.

"Just let us know where you are, pick up the phone, attend a police station, we just need to know you're safe and well."

ACT Policing has urged anyone who knows the couple's whereabouts or can provide any information about them to contact police immediately on 131 444.