CityFibre believes that the government's fibre broadband ambitions can be delivered.
Alex Blowers, Head of Regulatory Affairs at the provider, believes ministers are aiming to ensure ten million homes have access to fibre-to-the-premises (FTTP) by 2025.
Speaking at a Westminster eForum event on broadband policy and strategy, he described this target as "challenging but achievable", Computer Weekly reports.
However, he said this can only happen if there is a "radical policy rethink", as Openreach's FTTP economics are "fragile".
"We won't get to a national rollout by relying on Openreach alone," Blowers said.
"We should cherish the change of sentiment in Openreach and its recognition of the need to invest in FTTP, but other sources of investment will need to come about."
As a result, Blowers believes the industry needs to "evolve towards a more collaborative model", which includes both central government and industry regulator Ofcom.
Speaking at the same event, Ofcom's Director of Strategy Clive Carter said it is "absolutely open to a range of alternative ways of skinning this cat", such as network sharing, cost reduction and co-investment.
"We are not wedded to one vision of the future; we need to enable people to try those different commercial models," he stated.
Openreach is currently consulting with communications providers to identify the level of demand for a major full-fibre deployment.
The infrastructure body is engaging with stakeholders both to gauge demand for full-fibre within the industry and devise new investment, risk and cost-sharing models.