The European Union has warned China that it may take "additional steps" in response to Beijing's move to grant itself a veto over the selection of Hong Kong lawmakers.

China has moved to grant itself veto powers over selecting Hong Kong's politicians, part of a campaign to eliminate dissent and ensure a "patriotic" government in the city following huge democracy rallies in 2019.

"The EU calls on the authorities in Beijing to carefully consider the political and economic implications of any decision to reform the electoral system of Hong Kong that would undermine fundamental freedoms, political pluralism and democratic principles," an EU spokesperson said.

Brussels has previously decided to limit exports of equipment that could be used for surveillance in Hong Kong and EU foreign ministers have discussed the possibility of broader sanctions if the situation worsens.

"As agreed by EU foreign ministers, the EU stands ready to take additional steps in response to any further serious deterioration of political freedoms and human rights in Hong Kong, which would be against China's domestic and international obligations," the spokesperson said.

"If enacted, such reform would have potentially far-reaching negative consequences for democratic principles and democratically elected-representatives in Hong Kong," the EU statement said.  

Legislation to allow China's communist rulers to vet all election candidates in Hong Kong was tabled at the opening of the nation's rubber-stamp parliament in Beijing.

It came a day after dozens of democracy campaigners in the financial hub - including former politicians - were jailed under a security law that was passed during last year's parliamentary session.

The new legislation includes a "qualification vetting system" that will promote "orderly political participation", parliamentary spokesman Wang Chen told reporters.

China had committed to giving Hong Kong a degree of autonomy when it reverted from British colonial rule in 1997.

However, it began moving quickly to dismantle Hong Kong's democratic pillars in response to huge and sometimes violent democracy rallies that paralysed the city throughout 2019. 

The introduction of the vetting legislation, expected to be approved next week, was quickly interpreted as one of the final nails in the coffin of Hong Kong's democracy movement.

"If the measures are passed, as I'm sure they will be, then the voice of the opposition will be effectively silenced," said Willie Lam, China analyst at the Chinese University of Hong Kong.

"This will effectively wipe out any remaining opposition."

The measure had been widely expected with Beijing officials stating in the lead-up that only "staunch patriots" - those loyal to the Communist Party - should be involved in governing Hong Kong.

The Chinese congress session opened with an annual address by Premier Li Keqiang, who made no mention of Hong Kong besides Communist Party boilerplate about the city continuing to enjoy a "high degree of autonomy".

The annual week-long gathering of roughly 3,000 delegates, held in the cavernous Great Hall of the People in Beijing, is China's biggest political event of the year.

The highly choreographed display is held to drive home the unquestioned domestic power of the Communist Party while updating China and the world on its economic, political, environment and foreign policy priorities.

The event takes place with China outpacing other major economies after bringing the coronavirus pandemic, which first emerged on its soil, under control through draconian lockdowns and mass testing.

Mr Li said the government was aiming for 2021 growth in the world's second-biggest economy of "above 6%".

"In setting this target, we have taken into account the recovery of economic activity," he told delegates in China's equivalent of a state of the nation address.

China's economy expanded just 2.3% in coronavirus-stunted 2020, but Mr Li noted the country was still "the world's only major economy to achieve growth" last year. 

Analysts believe China's economy could grow 8-9% this year.

China's finance ministry, meanwhile, revealed that the nation's military budget - the world's second largest after the United States - would increase 6.8% in 2021 to 1.36 trillion yuan (€175 billion). 

But China's official budget number is widely believed to be lower than true spending.

Mr Li made no direct mention of brittle ties with the US, China's trading partner and geopolitical rival, with all eyes now on how the relationship may evolve under new US President Joe Biden. 

China's Foreign Minister Wang Yi will hold a press conference on diplomatic affairs on Sunday on the Congress's sidelines.

The NPC session may consider a proposed revision to wildlife protection laws that would permanently ban eating most wildlife, amid the belief that the pandemic came from an animal host.