The All Blacks have injury concerns over loose forwards Kieran Read and Adam Thomson ahead of next month's World Cup, after their defeat to Australia in the Tri-Nations decider.

No.8 Read suffered an ankle injury and blindside flank Thomson damaged his elbow as they went down 25-20 in Brisbane on Saturday.

Coach Graham Henry said he was hopeful Read would be able to play at least a limited role in the World Cup, but he was less optimistic about the chances of Thomson, who hyper-extended an elbow early in the first half.

Both players are to have scans when the All Blacks return home from Australia.

Read has been diagnosed with a high ankle sprain, but Henry has been told the Canterbury Crusaders forward is likely to be able to play some part in the World Cup, which starts on September 9, when the All Blacks play Tonga in Auckland.

"We're pretty positive really about Kieran. The doctor thinks he'll be able to play in the World Cup," Henry told reporters on Sunday.

"It may be a slow start for him but really I'm only speculating. I'm hopeful."

But Henry was not so positive about Thomson's prospects.

"It doesn't look good, we'll just have to wait and see," he said.

Henry would not speculate on who would be called in if either loose forward needed to be replaced, but Liam Messam is a likely candidate.

Skipper Richie McCaw emphasised Read's importance to the combination with Jerome Kaino, who was rested from Saturday's Test.

"Kieran's a big loss. He's a hell of a good player when he's fit and running around," McCaw said.

"That's the challenge you get in rugby isn't it? When guys get injured," he said when asked about the significance of Read's potential long-term unavailability.

AFP