Inspector Mel Aitken, the Area Commander for the West Coast, said a 45-year-old man was arrested "without incident" just before 3pm today on Old Christchurch Rd, north of Hokitika.
Earlier in the day, armed police descended on Arahura Marae, between Greymouth and Hokitika.
They were looking for George Sean Warren, who is alleged to have fled after Hayley Williams (43) was shot at a house on Marsden Rd, south of the Sinnott Rd intersection, about 4pm yesterday.
Police said several children were at the house.
Insp Aitken said a vehicle sought in relation to the shooting had been found and was being examined. However, officers were still looking for a weapon.
An associate of Warren's was helping police with inquiries.
Insp Aitken said police believed Ms Williams and the alleged shooter were known to each other, but that had yet to be confirmed.
"Police are doing everything we can to support the family during this difficult time."
Insp Aitken said police were grateful to the public for their help, and as a result were able to make an arrest within 24 hours of the shooting.
Invesitgators would be at the scene of the shooting for about a week.
