The Wales coach, Warren Gatland, thinks his defending Six Nations champions can improve in this year's tournament, which begins on 7 February.

Wales, who won a second grand slam in four years last season, play Scotland at Murrayfield on 8 February.

"We still think there's a 20-25% improvement in terms of intensity in the next two or three years," said Gatland, who was attending the tournament's launch in London. "So for me that's really exciting as a coach and hopefully for the players as well."

Wales were the only home union to beat one of the southern-hemisphere giants last November, when they defeated Australia after losing to South Africa and New Zealand.

"Given a small playing base compared with the best teams in the world, physically we have to be as good or better than the southern-hemisphere teams," Gatland said. "It's [about] learning to play and train at a higher intensity and the great thing about the autumn series was we played the three best teams in the world.

"We were tired. Physically we were really spent. You get a couple of weeks off, but that's all the southern-hemisphere teams do and then they go through it again."

Gatland said the Welsh Rugby Union had been aggressive in arranging fixtures against the southern-hemisphere teams. "It hopefully sets us up to do well in the Six Nations but also in preparing us for the World Cup in 2011," he said.

Gatland said all his players should be fit by the time, on 4 February, that Wales announce their team to face Scotland.

The Ospreys full-back Lee Byrne, a contender for the British and Irish Lions' Test side in South Africa in the summer, the wing Mark Jones and James Hook, who will compete with Stephen Jones for Wales's fly-half shirt, are all recovering from or carrying injuries. The centre Gavin Henson and scrum-half Mike Phillips have recently returned from long lay-offs.

Gatland said he had not yet thought about his selections for the Scotland game but he did confirm he had discussed a playing programme with the 33-year-old flanker Martyn Williams. Gatland persuaded the Cardiff Blues player to come out of retirement last season. The coach said the experienced openside could still be playing, at 36, in the next World Cup, in New Zealand at the end of 2011.

"The tag of favourites is something you can't hide away from," Gatland said of his side's status before the Six Nations. "We've got to address it and accept it. We are Six Nations champions and teams are going to be gunning for us. We would like to think that gives us some confidence and self-belief.

"We feel we are one of the best teams in the northern hemisphere, and the challenge for us is not to run away from it, but to embrace it. If we want to be considered one of the best teams in the world, there is going to be an expectation on us to perform from game to game and tournament to tournament.

"The last 12 months has been about getting some pride and respect back into the jersey – that was the No1 goal for all of us, and I think we've achieved that. We wanted to give the fans something to cheer about. There is a huge amount of expectation on us, and the fans deserve a Welsh team that goes out there and plays with pride."

Wales have ever achieved back-to-back grand slams. They face Scotland and England within six days at the start of this year's tournament.

"We want to be as consistent as we can and keep building from what we've achieved over the last 12 months," said Gatland. "It is a tournament of momentum. You win one or two games, and you can build on that; you lose one or two and people start talking about the wooden spoon.

"You've got to really hit the ground running. It's about making sure you have done the preparation and are ready to go from day one. If you win that first game, you get a bit of confidence and momentum."

Wales's recent record at Murrayfield is not good. Gatland said: "We've already talked about Scotland as being a potential banana skin.

"I think some Welsh teams in the past have perhaps gone up to Scotland and there has been an expectation to get a result, but they have come back with their tails between their legs. We know, mentally and psychologically, the first game is massive.

"Scotland have made a lot of progress in the last 12 months. They played really well against South Africa in November, so it is going to be a very tough encounter."