As of Thursday morning, police believe two other men were in the vehicle at the time of the crash and remain unaccounted for, with search efforts ongoing.

One man, believed to be a passenger, escaped from the vehicle and reached the riverbank, where he was assessed by paramedics but did not require further treatment.

The incident occurs amid severe weather warnings in NSW, with heavy rain expected to cause minor to moderate flooding in parts of Greater Sydney and northern NSW, as this August marks Sydney's wettest in 27 years.

Currently, 28 flood warnings are in effect across NSW, affecting regions including the Mid North Coast, Northern Rivers, and Greater Sydney.

The heavy rainfall is driven by a weather system involving warm ocean currents off north-east NSW and Queensland, which is pulling in abundant moisture and contributing to persistent rain.

Meteorologists explain that an upper-level low-pressure system over northern NSW is responsible for high humidity and ongoing rainfall, complicating rescue efforts.

Authorities are urging witnesses or anyone with information about the crash to contact Hawkesbury Police or Crime Stoppers, assuring confidentiality.

Emergency services responded around 11:50 pm after reports of the vehicle entering the river, with one man in his 20s escaping and reaching the riverbank, where he was assessed by paramedics but did not require treatment.

Despite the successful escape of one man, two other men remain missing, and police believe there were at least four men in the vehicle at the time of the crash.

A car carrying multiple men crashed into the Macdonald River near Settlers Rd at St Albans, about 20km north of Wisemans Ferry, late Wednesday night, prompting a large-scale search for the missing individuals.

Search efforts involving the NSW SES and Rural Fire Service are ongoing, with authorities treating the incident as a flood rescue due to recent heavy rainfall and difficult rescue conditions.

Wisemans Ferry has experienced over 50mm of rain in the past two days, with more rain forecasted, which has contributed to the challenging rescue environment.

Light showers are expected to continue over the weekend, as conditions remain wet and potentially hazardous across the region.