Dozens of landowners were never informed by local government about plans to enforce a five-kilometre no-development zone north of the ACT border, they say.
NSW planning initially rejected The Yass Valley Council's proposal for what residents are calling a dead zone last month but is now reviewing the decision, the 5km Border Zone Planning Group said.
Of the more than 80 Yass landowners who attended a meeting held by the group on Sunday afternoon, not one said they had received pamphlets about the zone that were supposedly distributed in the area.
"The council told me [that missing my house] must have been an oversight," one resident said.
Notices were apparently put up in local shops and community spaces, including the post office.
The buffer zone would see land values undermined and plans for subdivision put to paid until the Yass Valley Settlement Strategy expires in 2036 or is reviewed, the border planning group said.
Landowners fear the NSW government would eventually be able to resume land in the buffer zone at dramatically low prices, with it being assessed for rural use only, when it did pursue urban development.
The intention for urban development is stated in the NSW government's South East and Tablelands regional plan.
It would likely, then, be given to the ACT government in exchange for a desperately needed water supply to Yass and Murrumbateman, allowing for "Canberra's industrial and urban slums" to seep across the border, the group said.
"You can expect the bulldozers to strip the native vegetation, displace or kill the native flora and fauna and turn the whole 150 square kilometres into one big housing development and industrial complex," an information document provided by the group stated.
Meanwhile, a housing development on the border at Ginninderry, which is exempt from the proposed zone, had an unfair advantage during the 20-year freeze as the only allowed cross-border development.
The group argues it would make better economic, social, and environmental sense to allow more development along the NSW border, to allow those who couldn't afford to buy in Canberra and don't want to live in apartments a cheaper option.
"We should look at [the Ginninderry] development and see if we're being treated equally to the rest of this land," secretary of the planning group William Ginn said.
The buffer zone would protect productive rural land, biodiversity and natural resources, maximise the urban containment of the ACT, and protect the approach to the ACT, the Yass Valley strategy says.
RU1 zoning would limit development along the NSW border to rural use, and set the minimum lot size at 40 hectares.
But Yass Valley Council's request to rezone the area RU6, which was rejected by the government, would have stopped the land from being used for intensive livestock agriculture, extractive industries and trucking depots.
This contradicts the intention to protect the land near the border, the group said.
"Why not let the ACT protect its own approach? Why do we, in the Yass Valley, have to protect it? What are we going to do, build a fence?" Mr Ginn said.
"I don't think the ACT government are doing that at all. I think that we should show them that we can do it properly. I think they've done a lousy job across the border.
"Talk about the bush capital, it's an environmental disaster."
Yass Valley Council mayor Rowena Abbey insisted that no 20-year freeze on the no-development zone had been put in place, and that discussions were still about enforcing the buffer zone.
"I'm not sure why you would think that we would not consult with the community the decision [about the 20-year freeze on development]," Ms Abbey said at the meeting.
"It's not the council's decision alone."
It is understood the Yass Valley strategy would have to be reviewed in order for the 20-year enforcement of the buffer zone not to take place.
with Kirsten Lawson