Comments by embattled leader come as protesters plan to take to the streets throughout the weekend.

Hong Kong’s embattled leader Carrie Lam has said continued anti-government protesters could cause a swift and prolonged economic downturn, as a weekend of new demonstrations begins.

The chief executive of the Chinese semi-autonomous territory said on Friday she had held talks with business leaders who expressed concern about the long-term effect of the protests, with one businessperson likening the unrest to an economic “tsunami.”

Lam, whose support for a bill to allow extradition to mainland China sparked the unrest, said the economic effect threatened to be worse than the 2003 SARS outbreak or the 2008 financial crash for the city.

“Compared to the economic downturn caused by SARS that we handled previously, even to the (2008) economic crisis, the situation this time is more severe,” she told reporters.

Her comments came as hundreds of demonstrators, mostly wearing black shirts, started to gather at the arrival area of Chek Lap Kok Airport earlier on Friday – the second time they brought their message to the international travel hub.

Demonstrators promoted it on social media with a mock boarding pass reading “HK to freedom” and “warm pick-up to guests to HK”.

First launched in April, the protests began in opposition to a plan to allow extradition to mainland China, but have since morphed into a broader movement seeking to reverse an alleged slide in freedoms in the city.

LIVE: Protesters rally at Hong Kong airport https://t.co/E0MTOhZBxM — Reuters (@Reuters) August 9, 2019

Extra security measures have been put in place at the airport before the latest rallies, with authorities preventing anyone without a boarding pass from entering the check-in area.

The gatherings across the city, expected to run over three days, have not been authorised, but the last demonstration at the airport passed off peacefully without causing flight disruptions.

Airport Authority Hong Kong earlier said that it was aware of the planned rallies but “the airport will operate normally”.

Al Jazeera’s Rob McBride, reporting from Hong Kong, said the main worry among Hong Kong authorities is not the protest at the airport, but the other unauthorised demonstrations expected across the city throughout the coming weekend.

“You’ve got to remember that many protesters go out, and they protest quite peacefully. The concern for the authorities is, as we go through the day, that there is a hardcore group of thousands of protesters, who seemed to get involved in clashes with the authorities,” McBride said.

Meanwhile, an email attributed to an unidentified government spokesman said the government and the travel industry were working to minimise disruptions and “all stand ready to welcome and assist visitors to Hong Kong any time”.

As protests have become increasingly violent, several countries have upgraded their travel warnings for Hong Kong, with Washington this week urging its citizens to ‘exercise increased caution’ [Vincent Thian/AP]

Drop-in tourist arrivals

But on Thursday, the government conceded that tourist arrivals dropped 26 percent at the end of last month compared with last year and continue to fall in August.

It's Friday and scorching outside, and there's a massive sit-in protest at the Hong Kong International Airport. This is the first of a planned three-day rally in the arrivals hall. pic.twitter.com/FcRbaTUsC1 — Mary Hui (@maryhui) August 9, 2019

The travel industry accounts for 4.5 percent of the financial hub’s economy and employs about 250,000 people, or about seven percent of the total working population.

According to Lam, the effects of the mass protests have hit the Hong Kong economy harder than the 2008 SARS epidemic

Flanked by business leaders, Lam told the media that downward economic pressure had hit like a “tsunami”.

She added that she was worried about the long-term economic consequences of the protests.

On July 26, thousands of people of Hong Kong, including flight attendants, also rallied at the airport to “educate” visitors about the protests that have gripped the semi-autonomous Chinese territory.

The weeks of demonstrations pose the biggest threat to Beijing’s authority since Hong Kong’s handover from the British in 1997.

And as protests have become increasingly violent, several countries have upgraded their travel warnings for Hong Kong, with Washington this week urging its citizens to “exercise increased caution”.