Concerns are growing for a missing Waihi Beach woman who has not been seen since Sunday night.

Kelly Ann Sinclair was last seen leaving a friend's house in Katikati about 11.20pm on April 6.

Kelly Sinclair was last seen on April 6.

Police say the woman was heading to a friend's place in Mount Maunganui to stay overnight but never arrived.

'The last person to see Kelly said she seemed to be in an emotional state and her friends and family have not heard from her since,” says a statement from police.

'Kelly's cellphone is either switched off or flat and her family and friends have said it's unusual for her not to be in contact with them.”

Kelly was last seen in a Blue 1997 Audi A3 registration number DBM787.

Anyone with information about her whereabouts is asked to contact their nearest police station.