British and Irish Lions prop Mako Vunipola has insisted that he is far from certain of a start in the first Test against Australia next week.

The England international was at one stage the only loosehead prop left in the squad due to injuries to Cian Healy and Gethin Jenkins.

However, with Alex Corbisiero and Ryan Grant being called into the side as replacements, Vunipola is adamant that he must continue to work hard for his spot in the starting lineup for the Wallabies clash.

"Definitely not. The coaches wouldn't have brought out Alex and Ryan if they didn't think they were good enough to play in the Test series. I've just got to keep my head down and keep working hard," Vunipola told the official Lions website.

"Every player wants to play in the Tests. I knew with Gethin Jenkins and Cian Healy here, two solid Test props, that I'd have my work cut out - I knew I would have to work hard to push for the Test team. It's been going well so far and hopefully I can keep it going.

"To get three games in a row is great and I've had more chances than most players. Personally, the coaches seem happy with what I am doing so far, although obviously there is still room to improve and I need a good performance on Saturday. Every chance you get to pull on the red Lions jersey is a chance to push for the Test side. This game is no different - I'll just go out there and play the same game."

Vunipola will earn his third start of the tour when the Lions face the Waratahs on Saturday.