The call comes after three separate fires were lit in the Glen Warren Reserve in the past few weeks.
Senior Sergeant Jason McCoy, of Oamaru, said the woman was walking along the track at the reserve on Sunday when she allegedly noticed suspicious behaviour. She spoke to another person on the track about what she saw, but had not contacted police.
The other person she spoke to on the track contacted police about the discussion.
Snr Sgt McCoy pleaded for the woman to contact police.
‘‘We would love that lady to come forward and talk to us about anything that she saw,’’ Snr Sgt McCoy said.
‘‘They’ve stopped and spoken to another person on that track about what they’ve seen, but that [other] person hasn’t seen that activity.’’
Between August 11 and last Tuesday, Fire and Emergency New Zealand were called to three separate incidents in which fires were lit in a pathway of trees at Glen Warren Reserve.
Snr Sgt Jason McCoy said he was not aware of any further fires.
