Work is being jointly funded by Carmarthenshire County Council and the Welsh Government’s 21st Century Schools programme to remodel and refurbish the school.
The project is part of the council’s Modernising Education Programme (MEP) which aims to give every child in the county access to first class accommodation and facilities.
Local contractor Lloyd and Gravell were appointed to carry out the work which is due to be completed in December 2018.
Along with internally remodelling the school building to make better use of the space, it will provide improvements to the car park and landscaping.
Internal works include a complete reconfiguration of the building with new floors and ceilings, installation of a lift platform for wheelchair users, updating electrical equipment and a new ventilation system.
In addition the building will undergo a full decorating programme, and will provide specialist rooms for additional learning needs, design and technology and art, as well as new toilet provision.
When completed, the project will provide the school with 270 primary school places.
Education executive board member Cllr Glynog Davies said: “I’m pleased to see work underway to remodel Ysgol Pontyberem.
“It will provide the kind of high quality learning environment which will meet the needs of both pupils and teachers, in delivering the school’s vision and enhancing outcomes across a wide range of subject areas and skills.”
Council Leader Cllr Emlyn Dole said: “This is a major investment by Carmarthenshire County Council and the Welsh Government’s 21st Century Schools programme.
“The council’s Modernising Education Programme has invested £250million to date in Carmarthenshire schools, including the building of eight new primaries and two new secondaries.”