Thousands of new construction jobs in the North are awaiting the release of money from the DUP's deal with the Conservatives, industry experts said.
A £400 million windfall for infrastructure over two years has been agreed.
The centrepiece of the work will be at York Street Interchange in Belfast and will involve an underpass and bridge designed to improve links between the M1, M2 and M3. More than 100,000 vehicles pass through it daily.
Accountancy firm BDO Northern Ireland partner Brian Murphy said: "There is a huge opportunity here that is pregnant that needs to be crystallised."
The Conservatives signed an accord with the DUP after this year's General Election produced a hung parliament. It promised major new investment in Northern Ireland in exchange for the smaller party's support for the minority Conservative Government in key Westminster votes.
Business leaders have urged the extra money be speedily allocated for maximum economic effect.
Mr Murphy said: "Potentially thousands of new jobs in the construction sector are just waiting to open, subject to the release of these funds."
The future of Stormont power-sharing remains mired in uncertainty and John Armstrong, Construction Employers Federation (CEF) managing director, said that was being reflected in a property sector where some people are unsure whether to proceed.
"The lack of a Northern Ireland Executive and the lack of a fully agreed budget have undoubtedly impacted on the tendering opportunities available in recent months.
"That is simply unacceptable, given that in reality there is a public sector capital budget there to be spent - and a budget that itself is growing year-on-year."
He said the DUP deal had "huge potential" to create thousands of new jobs and develop key economic infrastructure that will enhance Northern Ireland's attractiveness as a place to do business in.
Mr Armstrong warned the construction "pipeline" may be beginning to slow down for a bit but its effect won't be seen for another year.
Invisible trade barriers are already becoming evident as some companies question whether they should tender for work in Ireland beyond the Brexit date of of March 2019.
Mr Armstrong said: "We cannot and must not allow these issues to exacerbate over the coming months as these concerns could extend further into materials transportation and costs or reciprocal arrangements around qualifications."