The London Wasps coach will be part of Warren Gatland's team preparing Wales squads for all their games up to and including the next World Cup in 2011.

Edwards will continue to fulfil the role of assistant coach in charge of defence he began before Wales' 2008 RBS 6 Nations Grand Slam success.

The new contract secures his relationship with Wales beyond the original two-year arrangement that was agreed last year.

Edwards, the 41-year-old former rugby league international who travels to South Africa with Wales for their two-match summer tour in June, said: "I am delighted that this deal secures my future with Wales until 2011.

"We have won the Grand Slam, but now it is time to focus on preparing to face the world champions and what a great challenge that is for us.

"I am extremely grateful to the managements of both Wasps and the Welsh Rugby Union for giving me this opportunity to work with these two marvellous teams.

"I can now focus all my energy on achieving a lot more success with both teams on the field where it matters most.

"My loyalty to Wasps is undiminished and I have already formed an extremely close bond with the Welsh team and the Welsh fans.

"There has been a lot of speculation about my future, but I feel very excited about working with my co-coaches and back room staff within the Welsh set-up.

"The Welsh squad has been great, fast to learn and have given everything asked of them even though that has sometimes been painful.

"There is still a lot of work to be done with the Wales squad, but they are a talented group of players and I am looking forward to the future."

WRU chief executive Roger Lewis said: "This is an important day for Wales. We are assembling a formidable array of talent to ensure we re-position Welsh rugby at the forefront of the global game.

"Shaun Edwards, in a remarkably short space of time, has gained a unique place within Welsh rugby.

"Shaun thoroughly deserves his fast growing worldwide rugby reputation as an outstanding coach.

"He has the capacity, attitude and integrity to make a huge difference to the teams he works with and the focus he brings to his task is legendary.

"We have a formidable coaching team in place under Warren Gatland and they know exactly what needs to be done to achieve the best from this current team.

"This contract with Shaun ensures he and Warren can work and plan towards goals which can be realised through to the next World Cup and that is an exciting prospect for the whole of Welsh rugby."