Carmarthenshire county council's planning committee is expected to make a decision about whether to allow housebuilders to develop a 336-home development in Ammanford today (Thursday).
Swallow Property Developments submitted a planning application to develop the new homes, including the provision of 70 affordable homes, on land at Tirychen Farm off Dyffryn Road, Penybanc, earlier this year.
As is usually the case with applications for large-scale housing schemes in many parts of the UK, the proposed development has received opposition from local residents, based primarily on claims that there is a lack of infrastructure to support the rise in local population.
But the site at Tirychen Farm has previously received planning permission for the construction of 141 new homes, but Swallow Development wants to replace the previous consent which it says does not make optimum use of it.
In a detailed statement submitted with the designs, planning adviser, Matthew Utting, said: "Swallow Property Developments feels that the site's existing permission represents a missed opportunity for all concerned - landowner and local authority,"
If the plans are approved, the number of households in Ammanford would increase by around a quarter.
At the time of the latest census, in 2001, there were found to be 1,242 households in Ammanford.