Five Spanish rugby players who were hit with heavy bans after confronting a referee following their heavily disputed defeat to Belgium are "on the verge of depression and cannot leave their homes", according to captain Jaime Nava.

Scrumhalf Sebastien Rouet was suspended for 43 weeks for physical and verbal abuse of Romanian referee Vlad Iordachescu after the 18-10 defeat in Brussels on March 18 allowed Romania to qualify for the 2019 World Cup in Japan at Spains expense.

Guillaume Rouet, who was convicted of the same charge, was banned for 36 weeks, while flankers Pierre Barthere and Lucas Guillaume and flyhalf Mathieu Belie all received 14-week suspensions for using threatening actions and words towards a match official.

World Rugby, which launched an investigation into the game and the appointment of Iordachescu, has delayed a decision on whether to order a replay - requested by the Spanish Rugby Federation - and is currently also investigating whether ineligible players were used in the tournament.

"The bans are what we expected but with all the circus that followed the game and the ineligible starting line-ups, I'm very annoyed and surprised that the first thing they have announced were the sanctions on our players," Nava told reporters at a publicity event on Thursday.

"I'm also sad because there are five team mates and friends that are feeling distraught. They won't leave their homes and they're on the verge of depression - some more than others because some of the sanctions are manageable, but the Rouet brothers (bans) are very harsh."

Spain can still qualify for the World Cup for the first time since 1999 but will need to beat Portugal in a playoff in order to qualify for a two-legged tie against Samoa in June.

None of the five banned players will be able to feature in those games.

No date has been set for the playoff and Nava said his players were struggling to focus while the investigation into the Belgium game continues.

"Right now no-one is thinking about the Portugal game or any other game," added the captain.

"We're going to take this issue, which is the federation's priority, (to) the end. We're going to see what conclusions World Rugby come to. We want to think that this injustice will be resolved."