Brian O'Driscoll has scored 18 tries for Ireland in 41 games

Irish star Brian O'Driscoll, rated by many as the best centre in international rugby, says he has yet to reach his peak.

O'Driscoll, one of the major successes of the British and Irish Lions' tour to Australia two years ago, will spearhead Ireland in their World Cup opener against Romania in Gosford on Saturday.

The 24-year-old Leinster midfield back is rated as a "pretty special" player by national coach Eddie O'Sullivan, but with that comes extra attention from opposing defences.

"I was a bit of an unknown quantity at the last 1999 World Cup ... four years down the line more people now know my game, my strengths and weaknesses," O'Driscoll said on Tuesday.

"I would think there is going to be less space for me here than I am used to, but I just have to deal with it".

But the Irish stylist warned his rivals that he can only get better, and is looking to produce that on the world stage in Australia over the next six weeks.

I'm an action rather than words kind of leader Brian O'Driscoll

"I hope I can reach the pinnacle of my game, I like to think that I can improve and go on to another strength, another level... I don't fancy hanging up my boots just yet," he said.

"I'm not putting pressure on myself to make a break, there are some fantastic finishers in our side and my goal in this World Cup is to put those guys into space and get them the scores".

O'Driscoll, who has scored 18 tries in 41 Test appearances, has captained Ireland nine times, but there is no resentment that he has to pass on the captaincy to Lions hooker Keith Wood at the World Cup.

"The label of captain is a lot more than meets the eye," O'Driscoll said.

"There's a lot of stuff behind the scenes that no-one gets to see and there's a large proportion of that I can hand back to Keith, but at the same time I will still try to lead as when I was captain.

"I'm an action rather than words kind of leader, I don't think in that regard I'm going to change my game".

He does deliver under pressure which makes him pretty special Eddie O'Sullivan

O'Sullivan knows he possesses the proverbial crown jewels in the attacking abilities of O'Driscoll.

"Everyone around the world respects Brian as an incredible game-breaker with ball in hand, but in recent times his game has rounded out as well and he's also putting other people into space," O'Sullivan said this week.

"He's still very young, he's 24, and he's captained his country and he's had a Lions tour here.

"He's very mature in terms of rugby but he's still a young player, and he's got a phenomenal career in front of him.