Ireland have concerns about the "unstable" surface of Japan's Hakatanomori Stadium pitch ahead of their final World Cup pool match against Samoa on Saturday, but said they had received assurances from World Rugby that it was safe to play on. Ireland's staff and players noted several worn patches during the captain's run on Friday and had been in contact with organisers about the issue at the Fukuoka venue. "I mean, you guys are pretty smart. You would have seen the pitch yourselves," Ireland scrum coach Greg Feek said on Friday. "[Scrummaging] is always my concern ... When it comes to a static kind of isometric position [with] a couple of big packs going at it, you're always going to be a little bit cautious and ask the questions and that's all we can do, really. "Prepare our guys as best we can, but also try to make sure the scrums stay up." Ireland loose forward CJ Stander said organisers had run out of time to make too much of a difference to the problem. "That grass out there is actually good grass, it's just not stable in a few points," he said. "We saw a few grass patches … It's actually A-grade grass, it's just how to put it down. I think it just needs a bit more time, [but] there's nothing we can do about that now." Ireland need a bonus point win to be assured of reaching the quarter-finals, but their final position in Pool A may be taken out of their hands by Super Typhoon Hagibis. Safety fears have already prompted the cancellation of two pool matches scheduled for Saturday nearer to the typhoon's expected trajectory, and Sunday's match between Scotland and Japan is also in doubt. If organisers call off the Scotland-Japan game, the teams will share the points, meaning the hosts would top Pool A. Even with a bonus point win over Samoa, the best Ireland could then hope for in Pool A would be second place, which would mean a potentially tougher quarter-final against the champion All Blacks. Japan would play Pool B runners-up South Africa in the last eight. Stander said he had accepted that reality and felt Ireland could not complain too much about their lot, having put themselves under pressure with their shock pool loss to Japan. "We let ourselves down against Japan," he said. "So it doesn't matter what happens. If we get a chance, an opportunity for the quarters, it's what we can do tomorrow. We can't look at other stuff, that's out of our control." Samoa captain Jack Lam has put country ahead of cash to be at the World Cup, revealing that he turned down lucrative French offers because of strings attached which barred him from rugby's global showpiece. The money was appealing to support his family, he said, but the clubs, which he did not identify, insisted he sever ties with Samoa. "It was a no-brainer," said Lam who was released by Bristol at the end of the last English Premiership season. "There were a couple of contracts in France that I could have taken but they had the condition that I had to turn down playing for Samoa in the World Cup and in the future as well," he said on the eve of their final match in Japan against Ireland. "I just couldn't do that to myself and the jersey and it just didn't cross my mind. It was a bit of a risk, especially for my family, but my missus and my family were all behind my decision." Lam, the 31-year-old backrower, said the Samoans who made it to Japan had formed a special bond. "For us as players, we want to leave with a bit of pride in the jersey. We still have a lot to play for, in terms of trying to qualify for the next World Cup and obviously for the future of rugby in Samoa," he said. "We've been together for a good eight weeks and it's pretty much been my family for the last two months, a great family.