Specialist search teams and dogs searched a forestry area in North Canterbury on Friday for a man they are seeking in connection with a homicide in Waiau.
Joanne Thompson, 46, was found dead on Monday after what police say was a prolonged and violent assault.
Police are looking for Ms Thompson's former partner Ross Simon Fraser, 43, in relation to the killing.
Detective Senior Sergeant David Long says staff are searching a forestry area where Mr Fraser had worked in the past.
"We have some general information about an area of forestry and riverbed area where he sometimes goes," he said on Friday.
"We're searching that area in case he is there ... probably about a four or five square kilometre area that we're searching today."
Police say Ross Fraser, described as caucasian, 170 centimetres tall, with shoulder length hair, should not be approached.