Patricia Dowdy is being investigated after a complaint was lodged by the late scientist’s family, reports suggest.
But the exact nature of the accusations remains unknown because the Nursing and Midwifery Council has taken the highly unusual step of banning the public and media from attending its hearing into them.
The hearing will decide if the nurse, from Ipswich, is fit to continue practising.
Ms Dowdy, 61, helped look after Professor Hawking for 15 years, although it is now understood she was suspended in 2016, two years before his death last March, aged 76.
She told the Mail on Sunday she could not talk about the hearing, which started last month and is due to last six weeks.
She said: “This is all very upsetting. Can I just say ‘no comment’ at the moment? I’m not supposed to talk to anyone.”
In a statement, the NMC said: “Hearings will usually take place in public. In some cases there are reasons why this doesn’t happen due to health.”
Professor Hawking, who was one of the world's great scientists, was diagnosed with a rare form of motor neurone disease at the age of 22 and was given just a few years to live.
The father-of-three, who lived in Cambridge, defied that prediction but was eventually confined to a wheelchair and became dependent on round-the-clock care.
In 2004, 10 of his nurses accused his second wife, Elaine Mason, of abuse after his family repeatedly took him to hospital with unexplained injuries including a broken wrist and gashed face.
It is not known if those injuries relate to the current hearing, which continues until 21 March.
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