Hong Kong's ardent pro-democracy protesters are attempting a "stress test" of the city's international airport this weekend as local and mainland authorities harden their resolve to quash the months-long unrest.

Key points: The stress test involves clogging up transport networks to and from the airport

The stress test involves clogging up transport networks to and from the airport Hong Kong Airport is one of the world's busiest

Hong Kong Airport is one of the world's busiest Hong Kong's business community is calling for an end to tensions as the city risks recession

The city's High Court on Friday said it was extending an order requiring public demonstrations to have the permission of authorities, with an aim to ban "those who want to deliberately obstruct or interfere with the normal use of the airport".

So in response, activists plan to disrupt transport to the international airport this weekend by all heading there at the same time.

"Go to the airport by different means, including MTR, Airport Bus, Taxi, Bike and Private Car to increase pressure on airport transport," protest organisers wrote online.

Hong Kong's airport, one of the world's busiest, was forced to close temporarily last week and hundreds of flights were cancelled or rescheduled when protesters and police clashed.

The airport authority published a half-page advertisement in major newspapers on Friday urging young people to "love Hong Kong" and said it opposed acts that "blocked and interfered with the operation of the airport".

It said it would continue to work to maintain smooth operations.

Canada restricts consulate staff

Meanwhile, the Canadian Consulate in Hong Kong said it had suspended travel to mainland China for local staff, just days after an employee of the city's British Consulate was confirmed to have been detained in China.

China's foreign ministry confirmed on Wednesday that Simon Cheng, an employee of the British mission, had been detained in the border city of Shenzhen, neighbouring Hong Kong.

Beijing has accused Britain and other Western countries of meddling in its affairs in Hong Kong.

Canada's latest travel advisory on Thursday warned that increased screening of travellers' digital devices had been reported at border crossings between mainland China and Hong Kong.

Protesters plan 'Baltic Chain'

Multiple protests are planned for Hong Kong on Friday, including a march by accountants to government headquarters and a "Baltic Chain" event where protesters will join hands across different districts in the Chinese territory.

In 1989, an estimated 2 million people joined arms across three Baltic states in a protest against Soviet rule that became known as the Baltic Way or Baltic Chain.

Loading

"The Baltic Way brought the world's attention to their cause and inspired following generations," the rally organisers said in a statement.

"We plead that you will not look away at this crucial time. Stand with Hong Kong."

The protests, originally over a now-suspended extradition bill to mainland China, have plunged Hong Kong into its deepest crisis since its British handover to Beijing in 1997 and pose a major challenge to Chinese President Xi Jinping.

Google announced on Thursday its YouTube streaming video service had disabled 210 channels appearing to engage in a coordinated influence operation around the Hong Kong protests.

Twitter and Facebook have also dismantled a similar campaign originating in mainland China.

Protesters fear the city's guaranteed freedoms are being dissolved by Beijing. ( AP: Vincent Thian )

The unrest, initially triggered by a since-suspended extradition bill, has broadened into a wider existential debate about Hong Kong's future under Beijing's rule.

Following Britain's handover of the colony to China in 1997, Hong Kong was to receive British-style capitalism, freedoms, and the common law system for a period of 50 years known as the "one country, two systems" principle.

These terms were set out in a document known as the Sino-British joint declaration of 1984, but by 2017, China said the document was not binding and had "no longer had any practical significance".

Loading

Hong Kong now risks first recession in a decade

Protesters have found workarounds to decrees banning them from directly protesting in the airport. ( AP: Kin Cheung )

Nearly three months of anti-government rallies have plunged the city into crisis.

Loading

It has brought a diversity of residents out in protest, which has included staff from the city's air carrier, Cathay Pacific, whom China has sought to identify.

Cathay confirmed on Friday that Rebecca Sy, the head of Cathay Dragon's Airlines Flight Attendants' Association, was no longer with the company.

Her departure follows the shock resignation of Cathay CEO Rupert Hogg last week.

The Hong Kong Confederation of Trade Unions said it would hold a news conference later on Friday to provide details of Ms Sy's departure.

The protests are already taking a toll on the city's economy and tourism, with the special administrative region on the cusp of its first recession in a decade.

Corporations, including big banks and property developers, have called for a restoration of law and order, while exhibitors are seeing widespread cancellations of events.

In the most recent case, international jewellers have sought the rescheduling of a huge trade fair with up to 40 per cent of exhibitors threatening to pull out.

Demonstrators have five demands: withdraw the extradition bill, establish an independent inquiry into the protests and perceived police brutality, stop describing the protests as "rioting", waive charges against those arrested and resume political reform.

Beijing has sent a clear warning that forceful intervention is possible, with paramilitary forces holding drills in Shenzhen, which sits on mainland China's border with Hong Kong.

ABC/Reuters