Residents in Sydney’s flood-ravaged northwest have been forced to face the impact of another major problem amid worsening weather.

A sewage pump in Sydney’s flood-ravaged northwest has been turned off amid worsening weather.

The move was made by Hawkesbury City Council on Monday morning for sewer pump station C on Macquarie St in Windsor.

Situated in Sydney’s northwestern outskirts, Windsor has been submerged under severe flooding for the third time this year.

People are being asked to refrain from any water activities in the sewer catchment areas.

Impacted regions include Windsor, South Windsor, McGraths Hill, Pitt Town, Bligh Park, Windsor Downs and Clarendon.

Sewage flowing into floodwaters can contain harmful microorganisms such as bacteria, viruses and protozoa.

Direct contact with sewage or surfaces contaminated by sewage can result in illnesses including gastroenteritis.

Rainwater generally contains contaminants from riverbanks and roads and it’s recommended people avoid all contact with the waters for a minimum of 48 hours.

Contaminated floodwaters can also heighten the risk of poisonings, wounds, gastrointestinal infections and skin or soft tissue infections.

Hawksbury Council is conducting regular checks on manhole covers and dislodged covers are being barricaded in local streets.

Impacted people in the region are being warned to stay alert for floodwater contaminated with sewage.

Handwashing after every contact with the flooded area is advised, along with using diluted bleach to sanitise contaminated areas and objects.

Parts of NSW are experiencing their fourth major flood in 18 months, with around 30,000 people subject to an evacuation order or warning on Monday.

Thousands of Greater Sydney residents have been left stranded after more than 150mm of rain fell in the last 24 hours in some areas across the state.

NSW Emergency Services Minister Steph Cooke said the flooding was “heartbreaking” for people across western Sydney, the Hunter and other regions who were only just recovering from the last heavy downpour.

“For many communities, this is the fourth flood they have seen in less than 18 months. Some of those images are truly heartbreaking; seeing people's homes, their lives turned upside down again and their livelihoods very much impacted,” she said.

“Our heart very much goes out to people and communities at this time, and I want to reassure those communities that we will be there with them right through the recovery process.”

A teacher has jumped headfirst into the waters of the north pole and taught children a lesson as a polar bear hovered over his shoulder.

A man has died in a storm where flash flooding and 8m waves have been recorded, with 100km/h force winds expected.

The heads of the nation’s disaster relief agencies have issued a warning for Australia after a briefing in Canberra.