"We have staff solely focused on this matter and we are very mindful of the period of time that has passed since Tom and his three children were last seen," he said.
Police continue to urge anyone with information about their whereabouts to come forward.
"We do believe there are people who know Tom that have vital information which will help us," he said.
"This is incredibly frustrating for police and we strongly urge those holding information to share these details with us as soon as possible."
The eldest sister of the three children is calling on police, Oranga Tamariki, the Ministry of Education and the Family Court to do more to help find them.
She has set up an online petition which has gathered more than 1500 signatures.
"They are now missing again. It has been nearly 4 months since they were last seen (114 days and counting) and all we want is to see the children and Thomas safely returned to their family," she said in a statement.
"It has been an extremely long time to have no guarantee if they are safe and well, or any idea where they are. We have gone from one extreme to another - a high profile search, reported on daily, to a multiple missing persons case that people are unaware of."
Anyone with information that can assist police to locate Tom Phillips is encouraged to contact police on 105 and quote file number 211218/5611.