The nation is falling behind its international competitors on internet access and affordability and more investment in communications infrastructure, like broadband, is needed, economists are warning.

Australia has been ranked 18th for its competitiveness in information and communications technologies in the World Economic Forum's Global Information Technology Report.

Australian Industry Group chief economist Julie Toth says Australia was ranked ninth in 2004 but its decline in ranking has been steady and disappointing during the past decade.

She says Australia needs to invest in communications infrastructure if it wants to raise its standing, and broadband is one area that could be improved.

"Our infrastructure is still lagging behind and that indicates that we do still need something like a National Broadband Network," she said.

"And we're still lagging behind on skills and I think that reflects the relatively low scores that Australia tends to get in the STEM skills area, which is science, technology, engineering and mathematics."

Ms Toth says the country performs well in internet security and fraud regulations but is behind more competitive nations in affordability and internet access for business.

"The business usage index, we're still only ranked 24th on that one and 49th on affordability," she said.

"Even though we've improved on that measure, affordability and access are still issues that the regulatory environment could help with."