The International Rugby Players Association says the reluctance of clubs to contract players from smaller nations during a World Cup year is not isolated to just one or two countries.
Manu Samoa lock Daniel Leo told Planet Rugby that some Pacific Island players are being pressured to declare themselves unavailable for internationals or asked to take a pay cut if they continue.
Players Association Executive Director Rob Nichol says players from second tier nations are vunerable because they often lose money by choosing to play for their country and rely on clubs for the bulk of their income.
He says it is happening all over the rugby globe.
"If you are a player that plays for anyone other than the All Blacks at a World Cup you are going to be absent this year, in New Zealand, from the ITM Cup so if you are a provincial union contracting a player who plays for Tonga or Samoa or the USA or a Canada for example, and you are looking to contract a player and he turns around and says, "well actually I was looking to go to the World Cup", the province has to release the player, and in the Northern Hemisphere the club has to release the player, and when you go to contract that player you're going to say, "well hang on a second - you're going to be away six or seven weeks so we're probably aren't going to pay you what we otherwise would have paid you. So, you know, you can understand that".
Rob Nichol says the issue is a commercial challenge that requires a commerical solution from Rugby World Cup and World Rugby.