SYDNEY, Jan. 7 (Xinhua) -- New South Wales authorities on Thursday were worried about an outbreak of mosquito-borne diseases as about 300 rural properties remained cut off by floodwaters around Coonamble in the northwest of the state.

    Emergency aircraft are helping with supplies and medical support as well as stock movement and fodder drops to isolated rural properties.

    An explosion in mosquito numbers has locals and government authorities worried about an outbreak of Ross River fever and other diseases.

    The medical officer for the Greater Western Area Health Service, Tony Brown, said an outbreak of Ross River fever is likely.

    "We've had the rain, we've had the water, we've had the mosquitoes starting to breed and people getting bitten," he said.

    "It takes a little bit longer, but I would expect there is a possibility from now on that we might see some Ross River fever."

    The mosquitoes have numbers on their side and there is little officials can do.

    "Widespread spraying is probably not an option in the short term, it takes a little bit of organizing to get that there," Brown said.

    "We're talking about areas in flood and access is not a simple matter."