Several airlines have told Sydneysiders travelling today to expect delays and cancellations as visibility at the airport has dropped down to just 400 metres this morning.

In western regions of the city, visibility is even worse — dropping to 50 metres in Richmond, Campbelltown and Bankstown.

Hundreds are taking to social media to share their eerie pictures of the dense haze, which has forced a ferry at Parramatta to turn back earlier this morning.

Those driving this morning reported poor visibility and dangerous conditions across the city.

One Uber driver told news.com.au he almost hit a median strip in the city’s south east because the fog descended so quickly during his overnight shift.

Drivers are reminded to put their fog lights on and take extra care on slippy roads from lingering rain overnight.

A Sydney airport spokesman tweeted this morning, saying customers should check their flights before travelling.

“Due to fog in Sydney this morning there are some delays,” he wrote. “Please check with your airline for up to date flight information.”

A Virgin spokeswoman told 9 News customers to expect flight cancellations this morning — adding that the fog is expected to clear by 8am, with flights disrupted until at least midmorning.

The fog is understood to be caused by Sydney’s consistent drenching over the past few days.

This has caused increased moisture in the atmosphere, which has combined with dropping temperatures to cause the fog which is now covering the city.