Allan and Brown investigated a wallaby carcass which had been hit by a vehicle on a Kyeburn road a few months ago.
More recently, there have been unconfirmed sightings further south.
There are three breeding populations in the Ida Range, which are "setting up camp and it is not something we can be complacent about".
"If they get a foothold, it will be a huge problem for Central Otago."
Wallabies are not restricted by creeks, rivers or altitude, unlike rabbits and some other pests, and can easily damage fencing.
Allan urged landowners to be realistic about how widespread the animals were and their impact on the land.
"From recorded incidences they are pretty widespread, but we have no idea how many there are, as they can be pretty well hidden under scrub."
He was pleased to hear the Otago Regional Council had received $6.28 million from Biosecurity New Zealand, with $370,000 of that to go towards eradicating wallabies in Otago.
Tender proposals for the funding close on January 27.
"Wallabies are sneaky, and even with funding it is going to be a huge challenge to eradicate them and I remain extremely concerned."
Allan has been in pest control his entire working life and had been impressed by the quality of work MPM had done in the area.
When he was offered a job with them, he moved his family to Maniototo, as he wanted to contribute to its success.
"The stakeholders in the Maniototo should be commended for having established MPM and continuing its work, as it is a real credit to them."