The CSW Broadand project aims to bring speeds of up to 24Mbps across Coventry, Solihull and Warwickshire in the West Midlands.
The project is being led by Warwickshire County Council, which has described it as a "one-off opportunity" to improve internet connections in some communities.
Rural residents and businesses that wanted improved broadband in their area should complete a special survey at www.cswbroadband.org.uk, it said.
Responses will be used to inform the design of the superfast broadband network that will be commissioned by Warwickshire County Council.
Paper copies of the surveys are also available through local broadband champions for those who could not access the website, the local authority added.
Councillor Alan Cockburn, of Warwickshire County Council, said: "The lack of broadband is a real barrier to employment and access to services for many who live or work in the rural areas.
He added: "The only way to improve things is to engage with the CSW broadband project by completing the survey."
Councillor Cockburn said the more responses that were received from an area, the higher the likelihood that it would receive improved broadband.
"This really is a one-off opportunity so we would urge everyone to get involved; otherwise some areas may miss out," he said.
Local broadband champions were spreading the word about the project and urging people to get involved in bringing improved broadband to their areasm said councillor Cockburn.
However, there were still significant gaps in the network that need to be filled.
The warning comes as the second round for Expressions of Interest in the government's Rural Community Broadband Fund (RCBF) enters its final two weeks.
Set up by DEFRA, the fund is aimed at rural communities who want to set up projects to improve local broadband provision is open to applicants.
It seeks to complement local broadband plans by bringing next-generation broadband access to a greater number of rural communities than might otherwise be reached.
To apply for funding, see the Rural Development Programme for England (RDPE) website. The deadline for expressions of interest is 6 July 2012.