British and Irish Lions prop Mako Vunipola says this weekend's second Test with New Zealand is now the "biggest game of their lives".

Warren Gatland's side are 1-0 down in the series ahead of the meeting in Wellington tomorrow. Vunipola says they're aware of how significant the 80 minutes will be after defeat in Auckland.

"We know that they took us on up front and got the upper hand [in the first Test]," he said. "It's up to us to stand up to them now.

"We're facing the best team in the world as we represent the Lions, there's no bigger honour for us as players.

"If you haven't got the right amount of energy out there, it'll show during the game."

Vunipola also spoke of the significance of the Test to himself personally.

"Growing up, I have to admit, I used to watch the All Blacks and be in love with them. Mostly because of Jonah Lomu. Being of Tongan heritage, I always wanted to be like him. 

"Being born in Wellington I had a lot of family over here and this is the first time I've been back since I left as a child."