Tour skipper Warburton has been managing a knee injury sustained against Ulster on April 7 and hasn’t played since that game at the Kingspan Stadium.
But with the first match of the 10-game tour to New Zealand now less than two weeks away, Warburton is back fit and took a full part in training on Monday in Ireland.
He confirmed: “I am fully fit, which is good. Last week in the camp in Wales I was pretty much doing everything apart from just the last little bit of contact stuff.
“But on Monday, I trained fully. I did full contact and I was absolutely fine. That’s all the boxes ticked, and now I can crack on. We’ve only one day here, but we can run pretty much two line-outs and get some team stuff going. We can do it all fully loaded. All the boys are pretty much up to speed.
“Now it means we can start building some momentum.”
Warren Gatland’s Lions are training at Ireland’s Carton House base this week prior to flying to New Zealand. Preparations are being stepped up to take on the All Blacks.
But head coach Gatland was dealt a big blow on Sunday when England No 8 Billy Vunipola withdrew from the Lions tour with a shoulder injury. His England team-mate James Haskell has replaced him.
Warburton said: “Billy was one of the guys I was really looking forward to playing with.
“He has been a massive player for Saracens. It is a big loss for us, but James is coming in – I think only Rory Best and Alun Wyn Jones have got more caps than him. It means we are very lucky.
“He is a player who I think will have a massive impact on this tour.
“I think it was a mature and brave call for Billy to make. There would have been a lot of pressure on him to go on tour, and he could have ended up going, perhaps playing the first two games and then could have ended up being sent home anyway with his shoulder.
“I think it is a brave call from Billy to put the squad first. He will be gutted, but he is young enough – he could perhaps go on another two Lions tours. I am sure he will be back, and in four years he will be red-hot for the Lions.
Warburton led the Lions to a 2-1 series victory in Australia in 2013. Facing Steve Hansen’s All Blacks in their own back yard is an altogether tougher challenge.
“I can’t wait to get out there. I am not going to be naive, I know it is going to be under the microscope more than four years ago,” Warburton added.
“Four years ago, I was walking around Melbourne and Australians were asking me who the British & Irish Lions were. I know there is not going to be anywhere in New Zealand we go and that question is going to be asked. Everybody is going to know who we are and what we are doing.
“That’s great. If you asked me in my career which Lions tour could I pick to go on out of any of them, if I could pick one, I would pick New Zealand. I personally can’t wait.
“Everyone is desperate to get into the Test side. You are going to have a lot of disappointed guys, but all egos are put aside and you help drive the team forward.”