In targeted messages to the federal government, AOC chief executive Matt Carroll says an extra $60 million a year is needed to help improve Australia's Olympic and Paralympic campaigns.

Carroll's bold statement comes on the same day an open letter, signed by 43 sporting greats, warned "high performance will inevitably transform into mediocrity" unless funding levels improve.

Ahead of Carroll's address at the National Press Club, Sports Minister Bridget McKenzie announced a $50 million boost for high performance sport across two years heading into Tokyo 2020.

But Caroll said that was nowhere near enough, warning the government's national sports plan, released in August, would fail if funding levels didn't increase.

"In the scheme of the federal budget of some $488 billion, this ($60 million) is not a lot of money," he said on Wednesday.

"An investment by government in sport is no different to investment in any other industry - the dividends are different but no less important for the economy and the country."

Australia's medal hauls have slipped at every Olympics following Sydney 2000, prompting the joint action from the AOC and athletes.

Under a new funding model from Sport Australia, more emphasis will be put on grassroots sports instead of winning medals at major international events such as the Olympics.

Swimming legends Ian Thorpe, Tour de France winner Cadel Evans, former basketball superstar Lauren Jackson and Wallabies great Phil Kearns are just some of the sporting icons to sign the open letter.

"When our glorious record of achievement at the Olympic, Paralympic and Commonwealth Games is substituted for a pathetic funding version of the Hunger Games, you know it's time to say enough," the athletes wrote in a letter published in The Australian newspaper on Wednesday.

Carroll also slammed the treatment of the Australian Institute of Sport, saying the program and its base in Canberra remains vital.

"The importance of sports science, sports medicine and technology in contributing to winning performances is clear," he said.

"Through deliberate funding neglect, the AIS is no longer pre-eminent."

Australian Associated Press