The anti-foreign sanctions law was rushed into force aims to protect Chinese individuals or organisations in the event that a country "uses various pretexts or its laws" to take "discriminatory" action against them.

No country is specifically named. But Beijing has accused Western nations of "suppressing" China's development, especially the United States. It has lashed out at "illegal and unreasonable" sanctions over human rights and flagged an urgent need to fight back.

Countermeasures listed in the law include denying visas, deportation, or seizing assets of those who formulate or comply with sanctions against Chinese businesses or officials.

It rules that authorities are not only able to target individuals and groups but can also take aim at their family members.

The law could also create severe compliance issues for multinational companies.

Part of the legislation prohibits those in China from going along with designated foreign sanctions. It acts in a similar way to a European blocking statute "which nullified the effect of US Iran sanctions within the EU"

This puts foreign businesses in a bind if they cannot legally comply with both US sanctions and Chinese prohibitions.