Berwick MP Alan Beith is concerned that dualling only part of the A1 north of Morpeth is sending the wrong message.
The Liberal Democrat MP pressed the case for A1 dualling at a meeting in the town last week organised by the Department of Transport and Highways Agency officials.
Campaigners have called for the key route to be dualled all the way from Morpeth to Scotland to reduce deaths and help boost businesses.
But after the meeting, Sir Alan said although any additional dualling would be welcomed, if some areas are ignored then it shows the road is not part of the strategic road network.
He said: “It appears that the main emerging options that will be put to ministers by officials are likely to involve dualling from Morpeth to Felton, and possibly as far as the North Charlton dual carriageway, but with a less favourable rating for full dualling of sections further north.
“Any additional dualling will be welcome, but if bad sections like the Mousen bends are not dealt with, it does not send a clear message to business that Northumberland and eastern Scotland are part of the strategic road network.
“And full dualling should be the ultimate objective. I will continue to press this case.”