The Fit for Work (FfW) service is to begin its nationwide rollout programme next Monday.
COVER's sister title WSB exclusively revealed it also appears that the programme will take longer to be completely installed than was first anticipated - likely completing towards the end of the year.
WSB understands that Rhyl in North Wales and Sheffield will become the first parts of the country to gain full GP access to the referral programme.
The pilot of the consultation service was initially limited to just 20 GPs in the Sheffield area, however Health Management, the FfW service operator, confirmed the next phase.
Speaking at the Health at Work 2015 conference, Health Management chief medical officer Dr Alasdair Emslie said: "Next Monday is the main rollout of the assessment service. It's going to happen regionally across the whole of the UK so by the end of this year certainly England and Wales will be fully covered.
"You in your areas will get to hear about it, there is a slight trigger with the election which is about to happen which is stringing things out just a little bit, but we're very excited that this is going to be rolled-out and available to you all as soon as we're able to."
Emslie noted that the firm was excited to be taking the next step and added "This is the start of something really special, rather than the end [of implementing the project]."