The old station would be knocked down to make way for the new one.
Only £8m has been secured so far out of £15m needed to build a new railway station proposed in Worcestershire.
There have been plans to build a new station in Bromsgrove on land close to platforms at the current station.
Advantage West Midlands (AWM) said more work to assess the scheme must be done before it would give any funding, letters obtained by the BBC show.
AWM, a regeneration body for the West Midlands, is just one body which could provide funding for the project.
All of its regeneration projects were scrutinized to ensure maximum value for taxpayers' money, AWM said.
In a letter to her constituents, the Conservative MP for Bromsgrove, Julie Kirkbride, described the decision as "somewhat disappointing".
Councillor George Lord, from Worcestershire County Council, said he was "extremely worried" about funding issues.
He said: "I hope it doesn't scupper the deal. It's essential. It's necessary.
"There's been an agreement in principle across the region about it. Now we just need the money."
The £8m has been secured through Network Rail, London Midland and other private sector money.
If proposals go ahead, there would be two more platforms than the current two and the number of parking spaces would increase from 70 to 350.
Plans to extend the electrification of Birmingham's Cross City Line to Bromsgrove have been approved.
BBC Midlands Today transport correspondent Peter Plisner said some felt that would make the new station a "much more attractive option" to those who might fund the new station scheme.