Protesters say they've already seen shooters doing the wrong thing on the first day of duck hunting season.
About 20 protesters have gathered at Moulting Lagoon on the East Coast for the season's opening.
Against Animal Cruelty spokesman Chris Simcox said one hunter took his time and shot at other ducks before checking on one he'd already downed.
This could prolong the suffering of the animal if it hadn't been killed by the initial shots.
``To our mind that's that not allowed,'' he said.
Mr Simcox said the group had been successful at scaring away ducks from shooters with whistles and flags.
About 20 shooters are understood to be hunting at the lagoon, which is the state's most popular spot for the activity.
Mr Simcox said activists and hunters understood each other's position and had a ``mutual agreement''.
``We don't antagonize them and they don't have any reason to do anything to us,'' he said.
Police had been in the area to monitor the situation and check compliance of hunters.
Tasmanian Field and Game Association spokesman Peter Darke could not be reached.