The incidence of osteoarthritis in Australia has grown in line with the national trend towards obesity, according to the Medibank Better Health Index.

The number of Australians living with osteoarthritis has soared over the last nine years, in line with the growing number of obese, according to Medibank data.

Figures released on Monday by the national private health insurer shows since 2007 the incidence of the painful condition increased from 6.2 per cent to 8.5 per cent.

This equates to more than half a million additional cases of osteoarthritis - the most common form of arthritis - across Australia.

The incidence has grown in line with the national trend towards obesity - with 28.4 per cent of Australians falling into the 'obese' category according to their body mass index (BMI), compared to just 25.2 per cent in 2007.

According to the Medibank Better Health Index, NSW recorded the sharpest increase in osteoarthritis nationally, rising from 6.3 per cent in 2007 to 9.5 per cent in 2017.

As a result, the state now has one of the highest incidences of the condition, falling only behind Tasmania where 12.8 per cent of the state's population are affected.

Dr Linda Swan, Medibank Chief Medical Officer, says it's concerning to see that the incidence of osteoarthritis is continuing to climb year-on-year, with almost one in ten Australians now living with the condition.

"We know osteoarthritis can be exacerbated by being overweight or obese, so it's essential that we continue to encourage healthy eating habits and regular exercise as these can help both prevent and improve osteoarthritis symptoms," Dr Swan said.

Her call was echoed by the Australian Commission on Safety and Quality in Health Care earlier this month when it released its new clinical care standard for treating knee osteoarthritis.

The commission's clinical director Dr Robert Herkes said life-style measures and pain-relieving medications were the gold standard for high quality care and that a total knee replacement should be considered a "last resort".