Wales veteran Tom Shanklin warned that the ever-improving Pacific Island teams pose a real danger to Wales' chances of escaping from their World Cup group.
Shanklin explained that while Pool D favourites South Africa will prove a stern test, the likes of Samoa and Fiji cannot be underestimated at the September-October tournament in New Zealand.
Minnows Namibia make up the five-team group, with only the top two qualifying for the quarterfinals.
"It's a tough, tough group. I look at that and think I'm glad I retired!", said the 31-year-old centre, who quit rugby in April due to a knee injury.
"These island teams are getting better and better year in, year out, with size and strength," added Shanklin, a member of the Wales side knocked out of the last World Cup by Fiji following a dramatic 38-34 loss in Nantes four years ago.
"Probably they don't play at a high enough club level but a lot of players for Samoa, Tonga and Fiji are (doing so) now, and that makes it even tougher," explained Shanklin.
"A lot of that is down to their top players playing for top teams in the northern and southern hemisphere.
"You need that experience and you need those players to show the rest of the team the values and help out the coaches with game plans and knowledge of the game."
Despite the challenge from Samoa and Fiji, ranked 10th and 14th in the world behind seventh-ranked Wales, Shanklin reckons his former colleagues have every reason to believe they can reach the last eight.
"If they play well enough, they will get out of the group. They didn't have the best Six Nations but it doesn't really matter because the World Cup's all about how you play on the day," the former British and Irish Lions tourist said.
Wales play three warm-up fixtures this month, starting with a trip to Twickenham on Saturday before a return match against England in Cardiff on August 13. They then host Argentina at the Millennium Stadium on August 20.
"These matches are about building momentum," Shanklin said.
"It's about trying to find the best combinations and build a bit of confidence so when you start the World Cup, you're on a high, everyone's happy."
Shanklin picked out Wales' 19-year-old Scarlets wing George North as a player who could shine in New Zealand.
"He's a young guy with plenty of potential. He's been out injured but he's come back, he's looking fit. I hear very good things about him and he could be the one to watch for Wales," he said.
"Many, many players make a name for themselves at the World Cup, such as Jonah Lomu in 1995. There can't be a bigger stage.
"It's a perfect opportunity to go out there and really stamp your mark on international rugby."
Shanklin, who had been with Cardiff Blues since 2003 before retiring, scored 100 points in 70 Wales appearances, making him his country's 11th most-capped player.
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