A policy that allows eco-friendly homes to be built in open countryside should be halted, a councillor has said.
Wales' One Planet Development (OPD) allows zero-carbon buildings to get planning permission.
But Pembrokeshire councillor Huw George does not believe developments are being monitored to ensure people adhere to the rules.
The Welsh Government said councils should determine applications in a "rational and consistent way".
It is a policy unique to Wales, with residents of the new buildings expected to demonstrate they can use the land to provide income, food, energy and waste assimilation.
Examples include a so-called "Hobbit house", with its owner gaining retrospective planning permission for the development in 2015.
Since the scheme began in 2010, 24 applications have been approved in Wales.
There have been 13 applications in Pembrokeshire, with five approved and a further three granted permission on appeal.
Four have been approved in Ceredigion, three in Carmarthenshire and two in Powys.
Mr George, who has seen five applications in his Maenclochog ward, said: "My concern is that the OPD policy is so wide that it is very difficult to monitor.
"At the moment, there are some in this area where the monitoring is so weak that we are two years in and we've had no reports and no response.
"Something has to be done to tighten this policy, to make sure there's a level playing field for those who live and work in this area.
"There has to be a moratorium on this policy now, to enable us to look, with Welsh Government to see if it's working."
He said while eco-houses were being given permission, farmers were not allowed to build cottages for their children on their land.
Pembrokeshire County Council's cabinet member for planning Phil Baker said: "We are concerned, with more of these applications being submitted, there's more work for our officers.
"I totally understand concerns from communities, particularly in the more Welsh speaking parts of the county."
Dr Erica Thompson of One Planet Council said the policy was governed by "very strict criteria".
"It's an opportunity for an existing farm or people looking for that return to the smallholding type of lifestyle," she added.
A Welsh Government spokesman said: "It is important these applications are determined in a rational and consistent way through the Local Development Plan (LDP).
"Pembrokeshire council is responsible for preparing the LDP and the policies within it and have the option of including policies to control One Planet Developments if it believes this is appropriate. "