A proposed three-lane M4 relief road has won the support of Newport Council, despite concerns about its environmental impact.
The Welsh Government is considering responses to the plans, of which two of three options are ‘broadly’ supported by the authority in Newport.
But concerns have been raised about noise and air pollution and the effect on the Gwent Levels landscape.
Newport council’s response to the Welsh government’s plans said an M4 relief road to the south of the city was to be supported in principle because of the benefits of reducing traffic congestion.
The authority says it would support the preferred “black” route along with an alternative “purple” route - both suggest building a three-lane motorway between junction 23 at Magor and junction 29 at Castleton, but via slightly different routes.
The council has asked for more detail on possible air and noise pollution, and said it was concerned about how the road would affect wildlife and public rights of way.
A third “red” option for a new dual carriageway would not go far enough to address traffic problems, the council said, which would be closer to homes, having a negative impact on public health.
It also ruled out a fourth “do minimum scenario” option.
Newport's cabinet member for regeneration John Richards said: “I have concerns relating to the prospect of another major road by-passing the city which may adversely affect our economic and regeneration aspirations.
“I also have concerns that sustainable public transport is not being considered together with the proposed route for a new motorway.
“However, I note that these concerns have been raised in the proposed response and have, therefore, no objection.”
The Welsh government is considering all responses to the consultation, which ended on December 16.