A player currently becomes eligible when they have lived in a country for three years.
World Rugby is due to vote in May on extending it to five, a move also backed by England.
"We believe five years is the right thing," said WRU head of performance Geraint John.
"That's the message passed over to World Rugby when we had the meeting.
"We were in the World Rugby meeting and Martyn Phillips was representing us and our strategy is five years."
The campaign led by World Rugby vice-chairman and former Argentina international Agustin Pichot.
And John says the idea suits the way the WRU want to manage talent in Wales.
"We feel it fits into our strategic plan in terms of what we're about here in Wales - developing our own, developing players that are already here in Wales, looking at talent and trying to keep that talent in Wales," he added.
While England and Wales support the plan it has been reported that Scotland and Ireland are opposed to the change.
John has also revealed the WRU have chosen to install the Wales A team as their new captured international side rather than the Under-20s.
It is a decision designed to make it more likely for England-based Welsh-qualified players to come back into the system because now playing for the Under-20s does not tie them to Wales.
The WRU have indicated their desire to restore the A team although there is unlikely to be a fixture this season for a second string side.
"One of the difficulties we found last year was if you play for Wales Under-20s you are captured so that means you can't play for anyone else," John told the WRU official website.
"We have looked at that and there are a lot of players who are based in England who are Welsh qualified.
"Because it (Wales U20s) was a captured team, the English clubs would not release them and we could not get them back.
"We have decided our Wales A team is our next captured side and that has allowed Welsh-qualified players from across the border to come back and be involved in the U20 squad.
"We have made that statement. I think it's a big plus and will attract those Welsh qualified players who are now living in England to eventually stay in Wales."
A plan to extend the period needed for a player to qualify for a country on residency has been backed by the Welsh Rugby Union (WRU).