Legislators from around the world have gathered on the fringes of the G20 summit in Rome to protest against the presence of the Chinese foreign minister, Wang Yi, and urge leaders not to let China off the hook over human rights abuses in return for Beijing’s cooperation on the climate crisis.

Many of those at the Rome counter-meeting have been banned from travelling to China as punishment for campaigning against Chinese repression in Xinjiang.

They are due to be addressed remotely by the Taiwanese foreign minister, Joseph Wu, as China steps up its threat to recapture Taiwan. Wu is on his first trip to Europe since 2019 and had been expected in Rome, but the Italian leg of his journey was cancelled with speculation that Rome was unwilling to give him a visa at such a sensitive time.

The Chinese president, Xi Jinping, was not attending the G20 summit in person. He has recently reaffirmed the reunification of Taiwan as a Chinese goal and increased military activity close to the island. China has described the Inter-Parliamentary Alliance on China (Ipac) counter-meeting as a gathering of secessionists.

Joe Biden, in an apparent breach of previous US policy, has pledged to protect Taiwan, but there has been ambivalence inside some western governments on how far to hold back from criticism of China in order to gain its cooperation before the Cop26 climate conference in Glasgow.

Some Chinese diplomats have said there will be consequences for China’s cooperation on climate if the country’s human rights record is singled out.

The gathering in Rome of Ipac – a body of about 200 global parliamentarians from different political perspectives – is the kind of event that will infuriate China. The group is due to hear from Penpa Tsering, the Sikyong of the Central Tibetan Administration, from the Hong Kong activist and former politician Nathan Law, and the Uyghur artist and activist Rahima Mahmut.

Dovile Sakaliene, a Lithuanian MP who was sanctioned by China in 2020, said: “We are here to ensure that the People’s Republic of China does not get a free pass at this G20. The leaders of the summit must realise very clearly what is at risk when they treat the PRC as an equal member of the club and what is the cost of making Uyghur genocide, Hong Kong and Taiwan bargaining chips. Let us not fool ourselves into trusting the PRC as a reliable partner in fighting the climate crisis, a state that sanctions human rights defenders and is currently imposing draconian population control measures.”

The former Conservative leader Iain Duncan Smith, also in Rome, described the Ipac bipartisan meeting as “utterly unprecedented”. He said: “Our collective purpose is to demand of the G20 governments that they publicly recognise the enormous threat posed by the People’s Republic of China.

“Whether it is debauching the financial system, disregarding global trading rules, committing genocide against the Uyghurs, trashing the international treaty on Hong Kong or threatening to invade Taiwan – the time has come to call the PRC out.”

How to handle China is a live issue among some of the G20 leaders, with Biden due to meet the French president, Emmanuel Macron, for the first time since the US formed a strategic Indo-Pacific alliance with the UK and Australia, Aukus, which excluded France.

The US was partly motivated by a belief that France was not prepared to take a sufficiently confrontational approach to China. Aukus scuppered an Australian $66bn deal to buy French-made diesel-powered submarines. The French government responded by recalling its ambassadors to the US and Australia. Macron has subsequently spoken to Biden twice by phone, and is likely to use his private meeting in Rome to demand that the US give a strong signal of support for a stronger European defence cooperation, a long-term French demand.

In Germany, China is also a live issue, with the likely new German chancellor, the social democrat Olaf Scholz, under pressure from the Green party, his potential coalition partner, to take a tougher line on Taiwan.

Scholz is due to attend the G20 summit alongside the outgoing chancellor, Angela Merkel. Germany has been one of the leading European voices backing economic ties with China.

Scholz is negotiating with the German Greens on whether or how to make Taiwan feature in any coalition program. Last week the EU parliament voted by an overwhelming majority in favour of a comprehensive strengthening of relations with Taiwan.

The Bundestag human rights committee last October angered China by holding talks with representatives of Taiwan. A few days ago, the Chinese embassy reminded Germany that China had “consistently supported Germany’s efforts to achieve national unity” and was hoping for “understanding” and “support” in relation to Taiwan. At the same time, the embassy claims that reunification is “the common wish of all Chinese people in the world, including our 23 million compatriots in Taiwan”.

The EU’s Indo-Pacific strategy released last month calls for pursuing “deep trade and investment relationships” with Taiwan, particularly in semiconductors.