Apple could be forced to disclose details of censorship requests from China and other nations after two major shareholder groups backed a proposal that would force the tech firm to make new human rights commitments.

The motion, set to be voted on by the company’s investors on Wednesday, was prompted by numerous allegations of Apple kowtowing to Beijing and blocking apps from being used by Chinese customers.

If approved by investors, the scheme could have implications beyond China and potentially expose details of tensions between Apple and other jurisdictions. The California-headquartered tech giant has regularly clashed with the US government, including most prominently over requests for iPhones to be unlocked.

The human rights resolution was put forward by campaign group SumOfUs, which cited several concerns about Apple’s relationship with the Chinese state in its submission to investors.

Apple failed in an attempt to block the vote from taking place. And now the Guardian has learned that the proposal has the support of the influential corporate governance groups ISS and Glass Lewis.

Together these two firms advise the world’s largest institutional investors on how they vote at company’s annual meetings, so their backing for the proposal is a coup for SumOfUs.

Ahead of Wednesday’s annual meeting, ISS and Glass Lewis have sent reports to their clients, seen by the Guardian, explaining why they should back the proposal.

Glass Lewis said: “[W]e believe that it would be prudent for the company to exhibit enhanced transparency around how it respects the right to free expression.”

In their reports, both Glass Lewis and ISS highlighted various news reports of Apple making apps unavailable in China.

In 2016, it emerged that Apple had removed its iBooks Store and iTunes Movies services from devices owned by Chinese customers. In 2017, it removed several virtual private network (VPN) apps, which were used by Chinese citizens to bypass state censorship apparatus. And last year the company removed HKMap.Live, a controversial crowdsourced mapping app that was being used by Hong Kong protesters to track police activity.

The SumOfUs proposal would force Apple’s board to prepare an annual report on the company’s policies relating to freedom of expression and access to information. The board would be compelled to state in the report whether they are “publicly committed to freedom of expression and access to information”.

They would also have to disclose a “description of the actions Apple has taken in the past year in response to government or third-party demands that were reasonably likely to limit free expression or access to information”.

SumOfUs believes the need to clarify Apple’s relationship with China is made particularly urgent by public outrage surrounding Beijing’s treatment of Uighur people sent to internment camps and pro-democracy protesters in Hong Kong.

Despite backing from ISS and Glass Lewis, SumOfUs still faces an uphill battle to pass the motion because it is opposed by Apple’s board, which includes the company’s chief executive, Tim Cook, and former US vice-president Al Gore.

Apple has issued a statement saying the proposal is “unnecessary based on the extensive information that is already publicly provided to our shareholders and users”.

The company currently publishes transparency data disclosing the number of government requests it receives by country for customer data and app removal.

For instance, Apple reported that between January and June last year, 288 apps were removed in mainland China for “legal” or “platform” violation. Apple stated that the majority of these requests related to pornography, “illegal content” and gambling.

But in its report to investors, ISS noted that the “quantitative approach to the company’s transparency report provides little context for the app removal requests from the Chinese government or explanation of the risks that may be involved”.

Apple said in its statement that free expression “is central to our company and its success” but that it is obliged to “comply with local laws and to protect the safety of our customers and employees”, including by removing apps.

The company said: “[W]hile we may disagree with certain decisions at times, we do not believe it would be in the best interests of our users to simply abandon markets, which would leave consumers with fewer choices and fewer privacy protections.”