He also expressed concern that the programme, which will be worth £3bn when it is rolled out, could be at risk if there is a change of government.
He said: "Our concern is that the election will intervene. Contractors have put teams together and talked to people in their supply chains.
"We are concerned that if there is a delay at this stage we will lose six months' work." A spokesperson for NHS Estates could not confirm when the pilot schemes will be advertised in the European Union's Official Journal.
He said: "We cannot say when the pilots will be launched. The project is still ongoing but I cannot say that it will be launched before an election in May." Under the proposed procurement route, framework agreements will be reached with a small number of contractors for projects valued at more than £1m. The agreements are set to last three to five years.
Tallis added that negotiations with NHS Estates over the pilot schemes in the West Midlands and north-west England had gone smoothly.
He said: "We have had a good series of meetings with NHS Estates and think we are ready to get on with it. It has been handled very professionally and collaboratively." This is the latest setback in Procure 21's troubled history. The Department of Health has already been attacked by small builders, which wanted the threshold for Procure 21 raised from £1m to £4m.
Medium-sized builders will be unable to tender for much of the work with the present threshold unless they work in the supply chain of a major contractor.