The Treasury has promised a funding announcement on the A303 Stonehenge and the Lower Thames Crossing works by the end of the year, after failing on its pledge to give an answer in the Spending Round.
Government officials had previously said that last week's spending update would allocate a budget to the multi-billion pounds schemes, which so far have only been granted development funding.
However Sajid Javid's announcement gave no further commitment to the sector on where the money would come from following a Treasury ban on PFIs, which were due to help pay for all of the Stonehenge and part of the Lower Thames and works.
The Government will consider the business cases for the A303 and Lower Thames Crossing alongside final decisions in the Road Investment Strategy 2 (RIS 2), which will be published in late 2019, a Treasury spokeswoman told Highways.
The funding for these projects sits outside the RIS 2 funding block, the Government has previously said.
Senior figures including MPs and Highways England chief executive Jim O'Sullivan have warned that the as yet unfunded schemes are at risk of missing their delivery schedules if some funding security is not announced soon.
The Stonhenge Tunnel is due to open in 2026 and the Lower Thames Crossing in 2027.
Mr O'Sullivan told the Public Accounts Committee that Highways England needs confirmation of public funding by the end of 2019 if these deadlines are to be kept.
The Treasury pointed out that week’s Spending Round was a fast tracked event to set departmental budgets for the year and said a full three-year Spending Review will now happen in 2020.
It also confirmed that the Government is maintaining the ban on the use of PFI or PF2.
A Department for Transport (DfT) spokesperson said: 'This Government is committed to investing in the transformative A303 Stonehenge and Lower Thames Crossing projects. Development work is continuing as planned.'
The DfT said business cases are being considered this year and funding arrangements will be considered in due course.