According to The Sunday Times, the whistle-blower was on the inquiry which concluded 456 people had their lives shortened after they were prescribed powerful opioids without medical justification.
They claim the syringes rapidly administered dangerous doses of drugs into the bloodstream.
The panel was warned a national helpline would have to be set up, as well as a compensation fund, if the full scale of the scandal emerged, and therefore “buried” suggestions by staff that the syringes were a problem.
Health Secretary Jeremy Hunt has rejected the allegations – and insisted the independent inquiry “would have said” if an issue with the syringe drivers was identified.
“We have to respect the fact that this was an independent panel led by Bishop James Jones… this is someone who has spent his life taking on the British establishment,” he said.
However, Mr Hunt added the government would look into all the evidence relating to the use of the syringes, which were banned in countries such as New Zealand and Australia.
He said: “We need to look at all the evidence that we have… Urgent advice was sent as far back as 2010 and the information I have is that they were taken out of use in 2015… We will look at if that was as quick as it should have been.”
The whistle-blower had told the newspaper: “Anyone who has lost their granny over the past 30 years when opiates were administered by this equipment will be asking themselves, ‘Is that what killed Granny?'”
Named Graseby MS26 and Graseby MS16A syringe drivers, they were easy to tamper with.
Reported incidents showed that, in some cases, they released a day’s dose in one hour.
The British medicines regulator issued a “hazardous product” alert in 1995 – with the NHS issuing a recommendation to recall them in 2010.
Despite this, they remained in use until at least 2015.
About 40,000 of the devices – a quarter of the worldwide total – were in the UK, the majority in primary care.
A 2008 paper by the NHS’s now-defunct Purchasing and Supply Agency (PSA) said the devices were an “essential component of palliative care”.
The PSA said the devices, which appeared “very similar aside from colour”, delivered drugs at different rates.
“Confusing MS16A (which delivers in mm per hour) with MS26 (which delivers in mm per 24 hours) can result in an infusion rate 24 times higher than required, and numerous adverse incidents of their type have been reported,” the PSA said.
It added there were safer alternatives.
The Gosport report said: “The panel has considered issues concerned with the particular syringe drivers, known by their trade name of Graseby, and is aware of the hazard notices which applied.
“The panel’s analysis does not rest upon any issue relating to these notices.”
A Department of Health and Social Care spokesman said: “While there is a range of statutory requirements to monitor and improve safe management and use of controlled drugs, we would not hesitate to take further action to improve safety.”
The panel told The Sunday Times: “These allegations are completely unfounded and without merit or support.”