Concerns have been expressed about further delays to the £91 million Bontnewydd-Caernarfon bypass.
The work was expected to start in late 2016 and be completed by the end of 2018 but was held up due to a disagreement between Natural Resources Wales and Welsh Government over wildlife.
Project contractors Jones Bros Civil Engineering have confirmed they are awaiting a date for the public inquiry before work can begin.
Arfon MP, Hywel Williams said: “The Caernarfon bypass is an important project for the area.
“In the long term it will ease the scourge of traffic congestion in the historic town centre, encouraging business growth and prosperity.
“In the short term it will provide hundreds of jobs.
“So it’s vital that local businesses get involved during the building stage so that as many workers as possible are recruited locally.”
Mr Williams has written to the Welsh Government to get a confirmed date for public inquiry.
Arfon AM Sian Gwenllian is hoping to raise the issue directly at the Senedd in Cardiff.
Mrs Gwenllian said: “If the timetable slips further, then work will have to be carried out over two winters and one summer instead of two summers and one winter, further adding to the delays.
“I want this economically important local project can begin as soon as possible.”
The Welsh Government said a decision of a date to start work is imminent.
A Welsh Government spokesperson said: “We are currently reviewing the responses received to the draft orders and will be making an announcement on the next stages shortly.”