Schraa is 44-years-old, and described as 1.92m, of slim-to-medium-build with sandy brown hair.
He was last seen about 4.30 on Sunday, May 24, in Aranui, possibly wearing a grey zip up hoody, dark blue jeans and black jandals.
"His family and police are concerned for his welfare," said a police spokesperson on Facebook.
Anyone who may have seen him or has information about his whereabouts should phone 105 and quote file number 200525/7090