Martin Sears said it was totally out of character for his son not to have contacted his family, and to be away from his boys for so long.
"As time goes on, we are all more seriously concerned for his safety and wellbeing, and it is critical that we hear something concerning his whereabouts soon."
Barry Sears, originally from Lower Hutt, is known nationally for his artistry in stained glass and lead lighting.
Detective Sergeant Bill Van Woerkom of Wairarapa police said he was believed to be travelling in a 1993 silver-grey Toyota Townace van, registration CZP104.
Mr Sears may be camping by the coast, a lake or river, and has associations with the Taupo and Gisborne regions