Plans are being discussed on Tuesday to build a £5.9m primary school in Wrexham to meet a growing demand for Welsh medium education.
There are already five Welsh medium infants and juniors schools in the county.
But they have been full or over subscribed for some time.
Ysgol Plas Coch has been oversubscribed for a number of years due to parents wanting to educate children in Welsh, said the acting head teacher.
Osian Jones, referring to September's new intake, said: "Normally we taken in 30 pupils but, for the third year running, we have taken in 60 pupils."
The school's capacity is 240 pupils but Mr Jones said there were currently 318 pupils at the school, with additional mobile classrooms, and the school hall being utilised as teaching space.
The planned new school would consist of 210 places to alleviate the pressure on Welsh medium schools such as Plas Coch.
Wrexham councillors are being asked to give their approval to fund £1.7m - 30% - towards the costs.
The main source of funding is to come from the Welsh Assembly Government - which has already been agreed in principle - subject to Wrexham council agreeing to its share.
A suggested location for the new school is in Gwersyllt, although nothing has been finalised.