Seven former Australia cricket captains have appealed to the country’s Foreign Minister Penny Wong over the treatment of former Pakistan Prime Minister Imran Khan, adding to growing concern among prominent cricketers over his detention.

Allan Border, Greg Chappell, Ian Chappell, Belinda Clark, Kim Hughes, Mark Taylor and Steve Waugh signed the letter to Wong, stressing that they were speaking “not as diplomats or political figures, but as former captains who felt compelled to speak up”. The former captains said they were not taking a position on the legal or political case against Imran, which they described as a matter for Pakistan. Instead, they focused on the broader humanitarian issue of how people in detention are treated, calling it “a matter of basic humanity, whatever their politics”.

The appeal comes less than a month after 22 former international captains wrote to Pakistan Prime Minister Shehbaz Sharif seeking better medical care for Imran.

That letter raised particular concern over reports that Imran had lost vision in his right eye and called for an independent medical assessment involving doctors of his choice. The former captains also urged authorities to honour weekly family visits reinstated by Pakistan’s Supreme Court and provide any treatment recommended following the assessment without delay.

It followed another appeal in February, when 14 former international captains wrote over Imran’s treatment.

Several former Pakistan stars, including Javed Miandad, Wasim Akram and Moin Khan, have also publicly raised concerns. Australia Test captain Pat Cummins has previously voiced his own concerns about Imran’s situation.