Scotland have brushed up their act ahead of Sunday's wet and wild World Cup opener with Ireland - by practising with balls soaked in shampoo.

Gregor Townsend's team are forecast to kick-off their campaign in Yokohama amid a torrential thunderstorm this weekend.

But the Dark Blues coach has been expecting things to get slippery regardless while his team are sweating it out in Japan.

The Scots have been based in Nagasaki as they complete their final preparations for the tournament, where temperatures of up to 33 degrees and humidity levels of almost 75 per cent have been recorded.

Now assistant coach Mike Blair has revealed the lengths they have gone to ensure there are no spills when they square off against Joe Schmidt's number one ranked side in the world.

He said: "We had the shampoo and conditioner out over the ball when we were back in Edinburgh. Since coming here to Nagasaki it's mainly just been water because the sweat is more of an issue.

"The wet is obviously not ideal, but the sweat is difficult to deal with.

"The conditions here in Nagasaki have been tough with the heat. It is likely to be wet and a bit cooler in Tokyo, but I never trust the weather forecast.

"Yesterday it said there was a 100 per cent chance of rain (on Sunday) and today it says a 50 to 60 per cent chance, which means it wasn't a 100 per cent chance the day before!

"So there will be a drop in temperature but difficult conditions to play in. It is good they have been training in the heat here, so they will be able to adapt to that as well." 

A downpour will favour Ireland with their structured approach certainly more than Townsend's free-flowing Scots.

But Blair insists the Dark Blues have a gameplan that will allow them to make a splash of their own.

"In every game we go in with different strategies depending on who we are playing and what the conditions are." he explained. "We have got a lot of personnel in our team who are very good in (wet) conditions like that as well.

"We are known as a team who want to play a lot of rugby and move the ball around quickly, and we feel very comfortable doing that. But we also feel we have got guys in the squad who are capable of playing in different conditions as required."

Ireland have had the recent bragging rights over Scotland, winning six out of the last seven contests between the teams.

Adam Hastings

But with both squads familiar with each other due to their frequent clashes on club and Test duty, stand-off Adam Hastings is predicting a feisty affair.

"They are a really well-drilled team and they have got a really good set-piece, and some good half-backs who try to control the game very well," he said.

"They are a big side as well so we have just to be really brutal around the contact area and try to rumble up their set-piece a bit. If we can slow down their ball and make life hard for their half-backs, that will bode well for us.

"In any international it is going to be feisty, but there are obviously rivalries there in these games. It will be an intense game and there will be a lot of big shots going in, which is what people want to see and it is what you want as a player as well, so I am looking forward to it."

RTÉ Sport will televise 14 live matches from Rugby World Cup 2019, including all of Ireland's matches, the knockout stages and a daily highlights show. RTÉ Radio will broadcast all Ireland's matches and you can follow the tournament via RTÉ.ie/sport and the News Now app.