Funding for the £130m Kingskerswell bypass cannot be guaranteed, a government minister has said.
Although previously approved, the south Devon link road scheme could be a victim of coalition cuts.
Devon MPs Adrian Sanders, Sarah Wollaston and Anne Marie Morris were seeking reassurances from Transport Minister Norman Baker.
But he said the scheme would have to be looked at "in the light of a tough spending review".
The controversial bypass for Kingskerswell has been debated for more than 50 years.
Those in favour claim it is vital to the economy of south Devon and it will also reduce congestion, improve air quality and improve road safety.
But opponents claim it would destroy the village of Kingskerswell and disrupt the ecology of the surrounding countryside.
The Campaign for Better Transport has also spoken out against the bypass, saying that costly road schemes are no longer viable.
Mr Baker said while the coalition strongly believed in the importance of a modern transport infrastructure, it could not ignore the current fiscal constraints.
"Any new government will naturally have its own views on which major schemes should be supported, but we will need to consider this scheme, I'm afraid, in the light of a tough spending review to come," the minister said.
He said the Department for Transport was committed to reforming the way decisions are made on which schemes to prioritise.
"The current fiscal situation also means we're having to look carefully at all future funding decisions on all transport schemes," Mr Baker told the three MPs.
"Until the spending review is concluded we will not be make any funding approval decisions."
He also warned nobody should assume schemes prioritised under the previous government's funding allocation process would be funded to previously published levels.
Mr Baker said there were "strong views" regarding the scheme and it was important to listen to both sides of the argument.
"The department can offer no guarantees, however I can give my personal assurance that I will consider carefully the case for the funding of the Kingskerswell bypass," the minister added.