Perplexed travellers this morning posted pictures of chaotic scenes at Sydney Airport after low-lying fog and crowds caused delays for hundreds of customers.

Passengers complained of facing massive queues at the check-in desks early this morning with unmoving queues of passengers stretching out of the terminal through the smoking area.

Pictures posted on social media by disgruntled passengers, show the terminal inside crowded with hundreds of people.

Some passengers endured delays of up to 70 minutes, with more than 50 flights delayed. Some flights were held back for up to an hour or more, while dozens of passengers had unexpected wait times of between 10 and 15 minutes to board.

As the airport struggles to clear the backlog this evening, the delays are still ongoing.

Virgin made several announcements to customers waiting at the domestic terminal and said the delays were due it being the busiest day of the year with “over 10,000 passengers”.

Flummoxed passengers were forced to queue for hours outside, as the line extended into the smoking area.

One passenger affected by the delays sent a pleading tweet to Virgin, asking, “Incidentally @VirginAustralia why didn’t we get a warning to come earlier to Sydney airport if the 2nd of January is such a known bad travel day?”

“Line barely moved in 45mins. This is a shambles,” wrote the Twitter user. Virgin responded that they were working to have guests “on their way as soon as possible.”

“We are experiencing longer than normal queues due to weather,” Virgin Australia tweeted.

Despite the chaotic scenes, a Sydney Airport spokesman told news.com.au that fog had caused delays to just a small number of flights around 7.15-7.30am.

Flights are returning to their regular schedule slowly, with the last delay being cleared before seven this evening.

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