A plan to create two national art galleries in Wales will cost up to £127m, according to a recently published report.

The Future Display of Visual Art In Wales assesses a long-held aim to develop a National Gallery of Art and a National Centre for Contemporary Art. It was commissioned by the Welsh Assembly Government; Amgueddfa Cymru - National Museum Wales (NMW); Arts Council of Wales; and National Library of Wales.

The report recommends sites in Newport and Swansea as possibilities for a National Centre for Contemporary Art. It says an independent trust should be set up to deliver the project, which could cost up to £39m.

According to the report, the best option for developing a National Gallery of Art is to devote the whole of the National Museum of Wales to art by moving the science collections housed there to a new museum in the north wing. The £88m price tag includes the money needed to refurbish the national museum to meet the brief of a National Gallery of Art.

Chris Delaney, a museum consultant and former heritage officer for Carmarthenshire County Council, is unsure about the need for two venues.

"I feel there is a need for a national gallery for Wales and a separate identity for that, but I am not sure about a contemporary art gallery," he said. "To have two institutions with an artificial boundary between contemporary and historic art seems a bit odd.

"Having a good network for showing contemporary art throughout Wales would be a better option and would be much more sustainable." Heritage minister Alun Ffred Jones said tough economic conditions and a reduction in lottery funding meant plans for both new galleries would not move forward until at least 2013.

NMW is currently investing £6.5m in developing the art spaces at the national museum. "What we are doing is no substitute for the National Gallery of Art, it is preparing the way for it," said Oliver Fairclough, the NMW's keeper of art.