The body, which was announced on Wednesday and has yet to be named, is due to start work in July after the wind-up of the CIB next month.
It will act as a forum for industry umbrella organisations such as the Construction Confederation and the Construction Industry Council. It is hoped that Egan's appointment will attract the client organisations that had shunned the CIB.
Raynsford told Building that the formation of the new body followed "extremely difficult negotiations" with construction industry bodies.
He said it would have been created earlier if trade associations had backed the proposal for a new forum, originally made by CIB head Chris Vickers.
Raynsford said the group would be separate from environment minister Michael Meacher's proposed safety body. If formed, this would push to attain the safety target outlined in February's government–industry safety summit.
Raynsford said: "That's a quite separate issue. I'm in regular contact with Michael to carry forward those commitments and how that's going to be handled." Meacher is backed by construction unions, who do not trust the industry to police its own working practices. It is understood that Egan was sounded out to lead Meacher's body.
Raynsford said his appointment of Egan, who wrote the influential Rethinking Construction report, would attract clients' organisations such as the Confederation of Construction Clients and the British Property Federation.
He said: "With such a highly respected client in Sir John heading it up, there could be no question that the client voice will be heard." The decision to wind up the CIB, first set up in 1995, followed the refusal of client body the CCC to join its board.
Raynsford said the body would cover four main areas: continuing the Rethinking Construction agenda; addressing the image and recruitment problem in the sector; health and safety; and extending the partnering and integration drive in the industry.
Egan's new role is his second industry post within two weeks. Last week he was named chair of industry portal Asite.
The new body was welcomed by the industry. CCC executive secretary Tony Pollington said: "In principle, a genuine strategic forum is what we have been asking for for a long time." Construction Products Association chief executive Michael Ankers said its focus on the four areas was positive. He said: "We think it is an appropriate list. You don't want 53 things to look at." A spokesman for the Construction Confederation said: "We think Sir John will bring a lot of clout to he new organisation." Industry sources said it was important that the body have a place for the unions as well as construction bodies and clients.
One source said Egan would have to curb recent negative remarks about the industry: "He has to make sure he makes encouraging noises about the industry."