Hansen, who will take up a position alongside former mentor Graham Henry with the All Blacks, has called for unanimous support for the new Wales Coach.
"Regardless of my opinion, the bottom line is that the WRU have made a decision that not everyone will agree with but a lot of people will," said Hansen. "Mike has been given responsibility to take over and we need the whole of Wales to get behind that.
"The WRU have gone through a process which has been difficult both for them and the candidates but this is the person they have come up with and we have got to support him.
"Mark Evans and Gareth Jenkins are obviously going to be disappointed, like players who are not selected, but it's important we move forward and support Mike as much as we can and see what happens."
Ironically Hansen has the Wales A and Ireland A Coach to thank for ending his record eleven game losing streak last year. Ruddock took over for the midweek friendly against Romania before the Rugby World Cup last summer, which Wales won 54-8, leaving him with a one hundred percent record as National Coach.
"Mike is a very good coach was good value when he was with us," said Hansen. "What he especially contributes is his coaching of the forwards. He's a leader of people and the WRU are comfortable with the decision they have made.
"It's not an easy job and he will have to stand up to the challenges. When I started (in February 2002) we set about building the foundations, which I think are now there. Just because you have laid the foundations does not mean you have built a house. You still need walls, windows and a roof and that is the next person's job.
"Most of the players we have in the set up will be around for the next seven or eight years and then we will see their true value. I'm sure Mike will want to change a few things but hopefully he will not have to rip up the whole page."
Among the changes Hansen hopes will not have to be made is regarding key members of the backroom staff. Hansen has urged both the Union to keep Skills Coach, Scott Johnson and Fitness Coach, Andrew Hore: "I would hope they both stay, they are important for the on-going continuity of the team."