"I [have] never seen any detention centre like this before," said the 30-year-old, who fled Iraq after it became known he worked for disgraced US military contractor Blackwater as an interpreter.
The Australian government and SERCO - a private contractor which staffs the facility - did not immediately respond to requests for comment.
The detainees expect to meet government officials on Thursday to try to resolve the dispute.
Hunger strikes are a frequent occurrence at onshore detention facilities, which house people who have run afoul of immigration law.
Last year hundreds of detainees at a centre in Sydney went on hunger strike against strict visitation rules.
Detainees have also used short-lived strikes to garner media coverage and put pressure on the government to close the facilities.
The government denies mistreatment, but has pledged a "ramping-down" of the country's "onshore immigration detention network."
Around 10,000 people were kept in the facilities in 2013, that number today stands at just over a thousand.
Australia recently closed the nearby Maribyrnong detention centre.
But detainees claim the new MITA facility, which housed 223 inmates according to the last government statistics from November, is worse.
In 2017, the Australian Human Rights Commission - a government body - reported the excessive use of restraints and limited space and privacy at the centre.
Refugee Action Coalition activist Ian Rintoul said there was "no excuse for the detention centres" and called for their closure.
Successive governments have upheld a decades-old policy of mandatory detention for "unlawful non-citizens" even for minor offences like visa overstays.
Critics say the policy is expensive, costing an estimated $237,000 per year for each detainee according to researchers at the University of New South Wales, and blurs the lines between an administrative solution and punitive detention.
But supporters say the centres serve as a deterrent and are necessary for effective control of Australia's borders.