Ireland won't change plans for clash with forward-heavy Springboks

South Africa used seven forwards off the bench to great effect when they inflicted a record 35-7 defeat on New Zealand in a warm-up game in London last month, but Easterby says Ireland will stick to their own plans.

"Every team has a strategy and it’s up to them to believe that is the right thing for each game," he told reporters on Wednesday.

"They believe that’s the way they need to set themselves out to beat us on Saturday, just like we will be planning the way to beat South Africa.

"It’s a talking point. I don’t think it changes anything for us. Hindsight will say whether it was the right or wrong thing to do."

The game is likely to decide who finishes top of the group and all but ensure quarter-final qualification for the victor.

"We always knew this was going to be the pivotal game leading up to Scotland (in their final pool match) two weeks after," Easterby said.

"We are just going about our business. We are really confident and trust what we have been doing, not just recently but in the last two and a half years. This is what we have been building towards."

Ireland go into the game as the number one ranked team in the world and on a run of 15 games without defeat, but come up against a South Africa team that has only conceded two tries in their last eight World Cup games.

"We know that when we play well and in a certain way we will be difficult to play against and difficult to beat. We will be looking to implement a lot of the stuff that you’ll have seen over the last couple of years in what we do on Saturday," Easterby said.