A PLAID Cymru AM has said he is disappointed the Welsh minister for transport will not provide further information about proposals to relieve the M4 around Newport.

Llyr Gruffydd, AM for North Wales, who sits on the Environment and Sustainability Committee, requested that Edwina Hart, responsible for economy, science and transport, be invited to appear before the committee again to address concerns outlined to her in a letter from another Plaid Cymru AM last week.

But a Welsh Government spokeswoman said: “It is not appropriate for the Welsh Government to engage in discussion on the draft Plan for the M4 Corridor around Newport during the formal decision making process.”

Mr Gruffydd said: “This is a serious matter that will have large economic and environmental repercussions for the whole of Wales, so I am severely disappointed that the Minister has given a blanket refusal to appear before the Committee or to provide any further information on the matter.

“The Assembly is not being afforded the opportunity to properly scrutinise the Welsh Government in making that decision. The decision will happen during the summer, and by then it will be too late for us to scrutinise.

“I am disappointed that as AMs we are not being allowed to do our jobs of holding the government to account. The Minister is refusing to appear in front of the committee, and is refusing to offer any further information to us.

“I am glad that the members of the Environment and Sustainability Committee have supported my request and that the Minister will be asked to answer the questions that the cross-party committee put to her.”

In a letter to Edwina Hart last week, Alun Ffred Jones AM doubted the lack of attention given to alternative solutions to the three options under consideration, also raising environmental and financial issues.

Responding to his letter, Conservative AM for South Wales East William Graham said: “Broadly, the ‘purple route’ was adopted over 20 years ago, and if the Conservatives had not lost the 1997 General Election we would be driving along an M4 relief road today.

“Thanks to the Conservative-led coalition government funds will be made available to the Welsh Government to make this a real statement of intent that Wales is open for business.”