The number of people contracting a superbug has risen by 37 per cent in the last year, according to Environmental Science and Research (ESR) figures.

There were 1042 cases of MRSA, or methicillin-resistant staphylococcus aureus, recorded in the month-long survey in August last year - 288 more than in 2010.

The increase was the largest single-year rise in the past decade and Medical Association deputy chairman Mark Peterson says it reflects the worldwide growth in superbugs.

"We've known about this increased resistance probably for a generation really and GPs and other doctors have become, over that period of time, much more careful with the use of antibiotics," he told Fairfax.

Doctors had been able to treat infections with antibiotics for 70 years, but it might not be so easy in another 70 years, he said.

Very sick or elderly hospital patients are most at risk from a superbug infection, as well as those who have an open wound, such as a bedsore, or a tube going into their body.

However, doctors are more worried about treating the lesser-known superbug, extended-spectrum beta-lactamase, or ESBL, which is resistant to a greater range of drugs.

Incidences have risen from 83 in 2001 to 578 in 2011.

Extremely sick patients and the elderly were more susceptible to ESBL bacteria, which adds to the difficulty in treating it as their bodies are battling other illnesses.