Female inmates were given the morning-after pill after male prisoners smashed their way into the women's section of the prison using hand-held grinding power tools during a mass jail breakout last month.

The Justice Department has revealed that the pill - used to prevent pregnancy after unprotected sex - was offered to dozens of female prisoners inside in Greenough Regional Prison, north of Perth, after a 12-hour riot.

The pills were offered despite the women saying they had not been sexually assaulted after the men broke in to the women's section of the prison.

WA Prison Officers Union acting secretary Paul Ledingham refused to say where any sexual assaults had taken place during the break in.

Female prisoners were sexually assaulted as male inmates smashed through women's section.

'If you have got a situation, riotous behaviour, that goes for 10 to 12 hours in a prison under the cover of darkness where males and females are concerned, I think anyone’s imagination might lead them to think that there were things going on,' he said.

During the riot, a female prisoner contacted Seven News using an office phone while male inmates broke into the women's section using angle grinders and other tools.

'Some of the girls are scared because you've got a whole bunch of aggro men running around,' she told Seven News.

Male inmates used power grinding tools to smash their way into the women's section.

The prison suffered million of dollars worth of damage after the riot (above)

'They climbed on to the roof and made their way into the girls' unit and smashed all the windows and everything.

'They're trying to throw bricks through windows and lighting all the couches on fire.'

A male prisoner then interrupted the phone call and attempted to justify the break in, claiming they'd only broken into the women's block to protect them.

The chaotic riot, which saw ten inmates escape from the prison, was the largest jailbreak in Western Australia's history.

All ten prisoners have been caught and are now facing charges additional charges.

The riot at the prison not only left a multi-million-dollar repair bill, but saw 10 prisoners escape