GAME Victoria has urged duck hunters to obey the law to protect the reputation of the sport.
The warning comes as 33 protected freckled duck were allegedly shot at Lake Lonsdale at the weekend.
Game Victoria director Simon Toop said when viewed in context, the rate of illegal activity was low on the season's opening weekend.
"On the whole, hunters are a largely compliant group but if they misbehave it damages the reputation of hunting," he said.
"We want to press that this sort of behaviour is not typical of the broader hunting public and we are urging hunters to report any illegal behaviour. "
He said Game Victoria would continue to survey Lake Lonsdale but could not confirm any additional wetland closures.
"We're having a look at Lake Lonsdale,'' he said.
"If freckled duck are still there and if they are in significant numbers, then we would make a recommendation.
"The freckled duck trigger point is 20 birds. There is another species - the blue billed duck - which has a trigger of 50 birds on a small wetland and 100 on a large wetland.
"We also take into account the size, the shape of the wetland, the habitat, the amount of hunting pressure, nearby refuges for wildlife we look at all those in combination and we make a decision."
He said one person had been caught at Lake Lonsdale and had their firearm seized and he expected they would be charged on summons.
Coalition Against Duck Hunting campaign director Laurie Levy said his team would continue to police the Wimmera's wetlands despite laws prohibiting them from protesting.
"We'll be out again and Lake Lonsdale will be included in where the team will be," he said.
He said the Department of Environment and Primary Industries lacked sufficient resources to police hunters and concentrated too much time on policing protesters.
"Agriculture Minister Peter Walsh said that everything was under control," Mr Levy said.
"The fact is the only way to stop freckled duck from being illegally shot is to ban duck shooting.
"The problem is that Peter Walsh spends 98 per cent of his time trying to crack down on us."
He said his group would continue to break the law in an effort to save ducks.
Mr Toop said Game Victoria visited 26 wetlands where 6850 hunters were shooting.
"From that we got low numbers of mostly minor offences; we detected 32 infringement notices on the opening weekend," he said.
He asked hunters to report any illegal behaviour they saw to the Department of Environment and Primary Industries.
Field and Game Australia director of policy and external relations Rod Drew said he was disappointed freckled duck were shot.