The coding tools could address some of Australia's skills shortages, experts said, even though additional training would be required.
GitHub reported the results at its annual developers event on Wednesday, also revealing that eight in 10 new users deployed AI in their first week on the platform.
The announcement comes after the Tech Council of Australia predicted AI could help to create 200,000 jobs in the country by 2030 and as the federal government considers what regulations will be required to govern its safe use.
GitHub, the world's largest software development platform, introduced AI tools in 2021 but the company said the technology had delivered its largest growth to date in 2025.
More than 36 million new users joined the platform in the year to August, bringing its user base to more than 180 million, according to its Octoverse report, and representing growth of 23 per cent.
Most new users adopted its AI software within their first week and GitHub Asia Pacific vice-president Sharryn Napier said the trend proved software developers did not view AI as an enemy.
"The story of 2025 isn't AI versus developers - it's about AI transforming how developers work," she said.
"More developers moving faster is good news for Australia as we continue to tackle our tech skills shortage and productivity challenges."
The company's newest users included first-time developers, students and people trying to solve tech problems who did not see themselves as software creators, GitHub chief operating officer Kyle Daigle said.
But veteran developers and open-source contributors were also using AI agents more often, he said, and in more places.
"Sometimes we can get caught up in the Silicon Valley nature or the North American nature of it but where we're seeing the growth accelerating so aggressively is outside of this single microcosm," he told AAP.
"This is the biggest year of growth that GitHub has ever experienced and it is incredibly global."
The company also revealed plans to expand its AI features, adding support for agents from companies including OpenAI, Google, Anthropic, Cognition and xAI.
The wider support would help software developers to choose the best tools for their tasks, Mr Daigle said, and could help to bring more clarity to what had become "innovative chaos" since the launch of generative AI tools.
AI had the potential to accelerate productivity over the next five years, he said, both in training more developers and helping others solve problems faster.
"I want to be able to do things that are not economically viable today or weren't years ago because the tools are there," he said.
"We're seeing more open-source projects created on GitHub than ever before.
