Cladding from four tower blocks in Swansea and three in Newport have now failed fire safety checks. It comes in the wake of the Grenfell Tower tragedy in London, which killed at least 80 people.
Fire safety in high rise tower blocks will be considered later in a one-day National Assembly inquiry in response to the Grenfell Tower tragedy in London.
The Equality, Local Government and Communities Committee will examine the safety requirements, guidance to residents and the current regulations in Wales.
Cladding tests on three tower blocks in Newport have revealed further concerns over the safety of the buildings.
Rhyl High School will be closed for the rest of the week, while cladding used on its new building is checked.
Swansea Council says cladding systems on its four high-rise block have passed 'whole-system' safety checks.