Four Namibia players currently playing professional rugby in South Africa have pulled out of the World Cup starting in Sydney on October 10.

Namibia coach Dave Waterston confirmed on Monday that hooker Hugo Horn, prop Jane du Toit, lock Johannes Theron and fullback Lean van Dyk had been replaced by Shaun van Rooi, Andries Blaauw, Phillipus Isaacs and Vincent Dreyer.

The quartet will not be allowed to play in the Currie Cup under International Rugby Board (IRB) rules.

"It is a blow to lose some of these players. Now we are going to have to hope we don't have too many injuries because it makes us less competitive at the tournament," said Waterston.

"Those players will not play in the Currie Cup, we are going to make an example of them. If they change their minds this week it won't get them back in the squad.

"It is out of my hands now, it is a Namibian Rugby Union (NRU) decision but this is the final squad for the World Cup."

Van Dyk said he would appeal to the NRU.

"I understand the IRB ruling which says I can't play for Western Province if selected by Namibia but I have spoken to the NRU and asked them to understand my situation," he said.

"It's a tough choice but I have made the decision to play for Western Province and further my career here. I'm 27 and rugby will not last forever."

Namibia open their World Cup campaign on October 14 when they play Argentina.