Several players in coach Warren Gatland's 30-man squad are set to make their first starts of the tournament.
The line-up for New Plymouth looks likely to include wings Leigh Halfpenny and Aled Brew, centre Scott Williams, plus half-backs Stephen Jones and Tavis Knoyle.
A new front-row of Gethin Jenkins, Lloyd Burns and Craig Mitchell could also feature, while there is a possibility of lock Alun-Wyn Jones starting at blindside flanker, with number eight Toby Faletau switching to openside if skipper Sam Warburton is rested.
Warburton, who has taken a breather from training on each of the past two days, is among several players who have enjoyed quality recovery time following last weekend's punishing 17-10 Pool D win against Samoa.
"The side that will take the field on Monday has to put pressure on other players," Wales assistant coach Rob Howley said.
"Competition has been the great ingredient this summer, youngsters and experienced players being put under pressure for places.
"Namibia is going to be a great opportunity for our players. We need to be accurate and play with tempo in our game.
"There was more tempo and continuity against South Africa. Against Samoa, it was a stop-start sort of match and we couldn't get continuity and tempo into it.
"We have to be clinical. I am sure we will get opportunities on Monday, and we have to be good enough to take them.
"I think we've been clinical up to a point throughout the last three or four months.
"We had 30 seconds in the opposition 22 against Samoa, and we scored one try. When you get into those positions, you need to score tries."
Former Wales captain Ryan Jones, meanwhile, is on course to make his World Cup debut against Namibia.
It has been a difficult week for Wales on the injury front, with full-back James Hook (shoulder) and flanker Dan Lydiate (ankle) both being hurt during the Samoa encounter.
But Ospreys back-row forward Jones looks likely to make his comeback from a calf muscle injury as part of Wales' matchday 22 at Stadium Taranaki.
He has not played since going on as a second-half substitute when Wales tackled England in their opening World Cup warm-up fixture at Twickenham almost seven weeks ago.
The 30-year-old trained fully today, though, during a public session at Waitomo Rugby Club, which nestles close to the famous Waitomo Glow Worm Caves around 50 miles south of Hamilton.
"It looks as if Ryan has come through the session well," Howley added.
"At this moment in time, he is fully fit and available for selection. Ryan was smiling and happy, which is always a good indicator.
"It looks as if he is up and running."
Jones, who missed the 2007 World Cup in France through injury, had initially not been expected to regain full fitness before Wales' final pool fixture against Fiji on Sunday week.
But his recovery ahead of schedule has given the Wales squad a boost as they look to remain on schedule for a potential quarter-final appointment with Ireland in Wellington next month.
And particular attention will focus on Halfpenny's performance after he emerged as a viable full-back alternative to Hook when replacing him at half-time against Samoa.
Normally a wing, the 22-year-old set up Wales' match-winning try with a searing break from inside his own half, while he also offers Gatland a long-range goalkicking option.
"Leigh is probably one of the most improved players in the past 15 months," Howley said.
"He didn't have a great experience against Ireland last year, but he came to the fore 12 months ago here in New Zealand. He seems to like it here, and he plays particularly well.
"He adds to the competition for places, which is a key ingredient.
"Leigh's counter-attacking led to the try (against Samoa), but he was also solid under the high ball and did everything right. That puts another name in the mix."
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