Issuing prison officers with cans of pepper spray will worsen the current "culture of conflict", a former prison governor has told BBC News.
John Podmore, who worked at high-security Belmarsh Prison in London, said there was "a real risk the pepper sprays will be turned on the officers".
Prison officers in England and Wales are to be given synthetic pepper spray to help deal with disorder and violence, under new plans.
Prison officers have praised the move.
But the announcement came as the Prison Governors Association (PGA) accused the government of failing to react quickly enough to a "crisis" in jails.
The chemical incapacitant known as PAVA has been trialled in four jails - Hull, Preston, Risley in Warrington, and Wealstun in North Yorkshire.
It will be carried by officers in all publicly-run prisons for men from 2019.
The Ministry of Justice said the move, which will cost £2m, followed the "successful" six-month trials.
'What next? Tasers? Rifles?'
But Mr Podmore said it was part of a "downward spiral", adding: "The POA [the trade union for prison officers] are already now asking for Tasers. What next? Sidearms, rifles in conning towers on perimeters?"
Asked whether officers should be able to defend themselves against violent prisoners, he told BBC Radio 4's Today programme: "Good luck with one can of pepper spray against half a dozen prisoners.
"There is talk [from ministers] of this being a deterrent - I think for many prisoners it will be a challenge and there is a real risk the pepper sprays will be turned on the officers."
The MoJ said the spray would only be deployed in limited circumstances when there is serious violence or an imminent risk of it taking place and officers will receive training before being allowed to carry it.
'More positive feel in jails'
In a speech to the PGA conference later, president Andrea Albutt is to acknowledge there is a "more positive feel" in jails after staffing levels were increased and security boosted.
But she will say there has been a "subtle campaign" to blame governors for problems and that ministers do not have the "humility" to admit their policies - which had included budget cuts - were wrong.
An MoJ spokeswoman said: "Senior managers in prisons do vital work and we are grateful for their dedication and commitment.
"We acknowledge the ongoing challenges they face and, as the president notes, we have taken meaningful action to address them which is starting to yield results."