The chairman of internet giant Google has thrown his support behind Australia's National Broadband Network (NBN).

The Federal Government has come under pressure from the Opposition because of the cost of the $36 billion rollout.

Speaking at a conference in Barcelona, chairman Eric Schmidt says Australia has shown great leadership on the issue.

"Australia is leading the world in understanding the importance of fibre," he said.

"Your new Prime Minister has announced that 93 per cent of Australians, which I guess are all the folks in the cities, will have gigabit or equivalent service using fibre, and the other 7 per cent will be handled through wireless services of a nature of LTE," he said.

"This is leadership from Australia, which I think is wonderful."

A spokesman for the NBN Co says Mr Schmidt's comments underline widespread international interest and support for the project.

Last week Telstra and the NBN Co finalised aspects of a deal to roll out the NBN.

They agreed on key commercial terms which pave the way for the NBN Co to use Telstra's assets and for Telstra to phase out its copper network.

Communications Minister Stephen Conroy described it as a "significant milestone".

He said the Government and Telstra had also also reached an agreement over measures announced last year to help with the transition to the NBN.

"These measures include a public information campaign, providing $100 million to retrain Telstra's workforce to deploy the NBN, and implementing the Government's reforms to deliver the universal services obligation and other public interest services," he said.