The Otago Regional Council yesterday discussed a report which listed four wallaby sightings in Otago in a six-week period.
Cr Scott said this was the latest indication of the situation getting incrementally worse.
Part of the issue was the area directly south of the Waitaki River was the domain of Environment Canterbury (ECan), and breeding wallaby populations had established there.
"And it seems to me that ECan is not doing its job."
He wanted the ORC to consider moving its biosecurity boundary to the Waitaki River so it could have the power to stop wallabies entering the region.
The council had discussed putting automatic gates on crossing bridges to stop the animals spreading, but had been told it was "too hard", he said.
Cr Graeme Bell said while regional council staff had co-ordinated with ECan staff, the councillors themselves needed to do this, too. Cr Doug Brown said there was an "urgency" to the problem.
"As you say, there is already a population south of the Waitaki.
"I think there are real issues up there and we need to address it because it’s going to get worse if we’re not careful.
"I just think this is something we should address sooner rather than later."
Acting chief executive Nick Donnelly said moving the biosecurity boundary was "not as simple as it might sound".
"There’s work we can do, but it would have to be funded by ECan."
The four wallabies were found at Georgetown, inland from Oamaru, the headwaters of Dunstan Creek, near St Bathans, and one was believed to have been dumped in Balclutha.
ECan regional biosecurity leader Graham Sullivan said the Canterbury council had a "joint work plan" with the ORC and an "active programme to prevent wallabies moving outside the containment area", which extended from the Rakaia to the Waitaki River.
"There is a focus on the south side of the Waitaki."
