HONG KONG - Chief Executive Carrie Lam Cheng Yuet-ngor warned on Monday that a "primary election" organized by the opposition camp might have violated the newly enacted National Security Law.

Her comment added to warnings from local authorities that the straw election over the weekend to pick candidates for the September Legislative Council polls was illegal.

The practice might have constituted subversion of State power, an offense among the four categories of crimes proscribed by the new security law, if its ultimate goal is to obstruct every single policy and initiative taken by the government by way of grabbing over 35 seats in the 70-seat legislature, Lam said.

"I have to put forward a warning. If that's the case, there is certainly a case to answer," Lam said.

The chief executive said the government had received complaints about the "primary election", including concerns that it may compromise the integrity of the upcoming election. People also complained about possible breaches of a ban on gathering of more than 50 people to contain the coronavirus, as well as breaches of privacy.

Lam said such an "election" was not part of Hong Kong's established political system, and that the government might take action after investigations.

The Constitutional and Mainland Affairs Bureau said in a statement on Monday that the government is conducting an in-depth investigation into the complaints relating to the primaries and will seek legal advice if necessary.

It said if there is any violation of relevant laws and regulations, the government will refer the case to law enforcement agencies for investigation and apprehension.

The bureau added that the ordinance of election in Hong Kong will not recognize nor approve the format, procedure and results of the so-called primaries.