Hong Kong's telecom sector has been drawn into the city's political crisis after the government signaled it was considering invoking emergency powers that would allow it to block networks and apps.

Government leaders earlier this week floated the possibility of invoking rarely used emergency powers to halt the protests that have racked the city for the past three months.

The Emergence Regulation Ordinance, described by one law professor as akin to martial law, would grant sweeping powers to government and police, including the ability to shut down communications networks.

It has sparked a strong response from the Hong Kong ISP Association (HKISPA), which represents telcos and data centers: The association warned in a statement that any selective blocking of apps or services would threaten the city's role as a global financial hub.

It said the complexity of the modern Internet, including technologies such as VPN, cloud and cryptographies, meant it was impossible to effectively block services "unless we put the whole Internet of Hong Kong behind [a] large scale surveillance firewall."

Restrictions on data traffic or networks would impose business and social costs, yet would not prevent users from accessing their intended services, it said.

Hong Kong's role as a major Internet and telecom hub in large part rested on its open networks. The city is the largest node in Asia's regional cable network, hosts more than 100 data centers and the region's biggest Internet exchange, and transits more than 80% of comms traffic for mainland China.

"Such restrictions imposed by executive orders would completely ruin the uniqueness and value of Hong Kong as a telecommunications hub, a pillar of success as an international financial centre," HKISPA warned.

Charles Mok, the IT industry's elected representative in the city legislature, warned in a newspaper column that the government could use the emergency powers to selectively target secure messaging apps such as Telegram -- widely used by protestors -- and local discussion forum LIHKG.

He said the emergency powers would allow the city's leader to take control of networks and shut down any communications.

Under the so-called "One Country Two Systems" formula that has applied since the city came under People's Republic of China (PRC) rule in 1997, Hong Kong has retained its own legal and political systems. This means that, unlike their neighbors across the mainland border, Hong Kong residents enjoy largely unfettered Internet access.

The British common law legal system has helped make it one of the world's biggest financial centers, its stock exchange having taken hundreds of Chinese companies public, including all three state-owned telcos. Hong Kong took the crown last year for holding the world's most IPOs.

The protests began in early June, initially against a proposed law that would allow local people to be extradited to mainland China. They have now broadened into a wider protest against the government and a demand for political reform.

 Robert Clark, contributing editor, special to Light Reading