The government is preparing to award a contract for its controversial Firelink project, which will establish regional fire control centres, by November.
The Office of the Deputy Prime Minister said the roll-out of new control centres is expected to begin in 2006 and be completed in 2008.
But it will face opposition from the Fire Brigades Union, which said the project is complex and could endanger lives.
Jim Fitzpatrick, parliamentary under-secretary of state at the ODPM, said, "The project will use the digital national radio solution provided by Firelink as its primary bearer for voice and data."
He added that Firelink would link to a project to deliver an integrated, resilient command and control system for the Fire and Rescue Service in England.
In a statement, the ODPM said, "Firelink is an important investment in wide area digital radio communications. The system will bring improved communications, particularly in terms of interoperability with other emergency services, and help provide a more resilient service."
But the Fire Brigades Union said creating fewer emergency control rooms would mean "less resilience and increased vulnerability".
Union president Ruth Winters said, "The government's track record on large technology projects is very poor. Its record suggests this project will be very expensive and may not work.
"Our ability to respond instantly to incidents could be badly damaged. It will not be benefits or tax credits being delayed, as happened after other government technology failures; it will be a frontline 999 service."
The ODPM would not comment on the union's reservations about Firelink.