Supply chain issues and time delays could mean the Welsh Government falls short in its plan to address Wales' housing crisis.
The Welsh Government has pledged to double the amount of money it spends on social housing to build 20,000 low carbon homes
It has committed to spending £250m during 2021/22 and the aim is some of the houses will produce more energy than they use.
When the plans were unveiled in August they were described as "ambitious" but now industry experts are warning they might have set an impossible target.
New research from the Chartered Institute of Housing Cymru has identified how significant supply chain pressures are impacting the ability of companies to on deliver on their commitments to build new homes.
Prices for materials such as timber, steel and concrete have rocketed by as much as 40% and almost 9 out of 10 companies are reporting problems in the supply chain.
The result is that some are delaying major constructions and revising contract conditions.
Catherine May, Tyfu Tai Cymru manager said: “Whilst we’ve strongly welcomed the clear vision set out by the Welsh Government to deliver 20,000 low carbon social homes, and significantly improve the efficiency of existing homes we can’t ignore the tension between that vision and the realities of the operating environment many providers of social and affordable housing are facing.
These pressures aren’t going to subside overnight, whilst the sector must continue to adapt to these challenges, so too must the Welsh Government seek to get ahead of these issues and create a focussed plan so that we increasingly find ourselves on a stronger footing to meet our shared ambition for housing in Wales.”
The Welsh Government says it's working with the sector to agree how it ensures work continues at pace.
Minister for Climate Change, Julie James said: "We welcome the report published by the Chartered Institute of Housing Cymru and are aware of the current difficulties of sourcing and cost of certain materials in the construction supply chain.
"We understand this is a global supply issue across all construction activity and we are working with our social housing partners to understand how the current situation is impacting on the delivery of new social homes and the maintenance of existing social housing stock.
"We need to find a proportionate way to support the social house building sector in the face of unprecedented cost pressures. I have indicated my support in principle towards this approach and we are working with the sector to agree how we can ensure that work continues at pace to build and maintain the social homes the people of Wales need."