There had been plans to dissolve both Shropshire and Telford & Wrekin clinical commissioning groups to form the new organisation by next April.
Health commissioners applied to NHS bosses last month, but have now expressed their disappointment and say they have been told the 'application is not strong enough at this stage to proceed in this timescale'.
It comes as Shropshire and Telford & Wrekin CCGs need to make cuts of 20 per cent to running costs to save £1.2 million.
It was announced earlier this month that David Evans had been appointed as joint accountable officer for both organisations and was expected to take them forward to becoming a single commissioning organisation.
But it looks like NHS England and NHS Improvement have now put these plans on hold.
In a joint statement, Dr Julian Povey, chair of Shropshire CCG, and Dr Jo Leahy, chair of Telford & Wrekin CCG, said: “We are both disappointed that today NHSE/I have advised that the joint application from NHS Telford & Wrekin CCG and NHS Shropshire CCG to become a single strategic commissioning organisation in April 2020 has not been successful.
“Following the NHSE regional panel meeting on Friday the view is that the application is not strong enough at this stage to proceed in this timescale.
"There was clear recognition of the hard work that had gone into the application and the progress that has been made given how late we entered the application process. We would like to echo this recognition.
“Given the support of our governing bodies, members and partners this is clearly disappointing news however, in line with our previous position, we will continue to develop a single management structure across both CCGs and work to bring teams together over the coming months with a view to reapplying to become a single strategic commissioning organisation as soon as possible.”
Health bosses say the creation of a single body is to support the ambition of the NHS Long Term Plan, however the proposals have been met with controversy.
Earlier this month the plans received only 'limited support' from the region's health scrutiny committee.
Members of Shropshire and Telford & Wrekin Council’s joint health overview and scrutiny committee were asked to Indicate their level of support for the proposals.
In response, Councillor Karen Calder, committee co-chair, said: "It's clear we can only say at this moment that it's limited.
"It does still feel like a work in progress. We would ask you to return with more information and assurances around the risks we have identified."