Hong Kong,  HSBC and Standard Chartered have given their backing to China's controversial national security law for Hong Kong.

On Wednesday, HSBC's Asia Pacific chief executive Peter Wong signed a petition backing the law which has been widely criticised, reports the BBC.

Although it is Europe's largest bank, HSBC has a strong presence in Asia, particularly Hong Kong.

HSBC "respects and supports all laws that stabilise Hong Kong's social order," it said in a post on social media in China.

The bank's full name is the Hongkong and Shanghai Banking Corporation and it has its origins in the former British colony.

While HSBC moved its headquarters to London in 1993, Hong Kong is still its biggest market.

Standard Chartered also has a strong presence in Asia, said the BBC.

"We believe the national security law can help maintain the long-term economic and social stability of Hong Kong," it said in a statement.

It added that "the 'one country, two systems' principle is core to the future success of Hong Kong and has always been the bedrock of the business community's confidence".

The two backings come as Japanese bank Nomura said it was "seriously" examining its presence in Hong Kong.

It is unusual for a bank to enter into political debate, particularly one as controversial as China's new security laws which many feel could mark the end of Hong Kong's unique freedoms, the BBC said in the report.