The season opens today, although most high-country rivers do not open until November, to allow rainbow trout to finish spawning.
Otago Fish and Game officer Morgan Trotter said the bad forecast on top of recent rain meant many rivers would be reasonably high and discoloured for opening day, especially in South Otago.
His advice was for anglers to head to North Otago, where rivers should be clear and fishable.
He hoped conditions would improve by Friday, allowing anglers to enjoy a good opening weekend.
There had been some changes to regulations for the new season, including the opening-up of the Kawarau River to fishing from boats, and a catch-and-release policy on the Lochy River.
The Dingle Burn and the Lochy had been designated as backcountry rivers, meaning anglers would need backcountry licences to fish them.
Confusion around the use of rubber chemical preparations had been clarified, meaning they could only be used in bait-only water, Mr Trotter said.
