The runners set out for a run in an area between Kawerau and Lake Rotoma around 10am. Relatives raised the alarm when they failed to return.
Two police search and rescue teams, as well as volunteers, launched a search for the trio around 4pm yesterday and continued throughout the night, Mr O'Reilly said.
Police had concerns for the runners as their were lightly-clad and temperatures were expected to drop overnight.
Extra search and rescue members joined the effort this morning.
"I would like to take the opportunity to thank everyone who has been involved in the past 18 hours, at a time when many of our volunteers and supporters are taking a well earned break to celebrate the festive season with their family and friends," Mr O'Reilly said.