With long and unpredictable shifts, it is often hard for workers in hospitality to keep track of how many hours they work.
It is a simliar situation for workers on unpredictable shiftwork in other industries such as retail or agricultural areas like fruit picking.
And that can become an issue, particularly if their employers are not keeping proper records and are underpaying workers.
But a new mobile phone app is aimed at addressing the issue.
The Fair Work Ombudsman, the body that handles complaints about workplace exploitation, has developed the app, called 'Record My Hours'.
Ombudsman Natalie James says it provides an easy way for workers to log how many hours they spend at their jobs.
"The way the app works is you set up your job, or your jobs if you have more than one, and you set up the address in your phone, and it will trigger effectively when you're in the workplace. All the data is stored on your phone. We don't have access to that data. No-one else has access to that data, unless you choose to send it to someone. So you might send it to us if you're worried that you're not being paid for all the hours you are working, or you might send it to your employer to say, 'Look, I just want to check that I have been paid, because my pay slip says something different from what my own records say."
While employers are required to keep proper records of hours worked, Ms James says, in some cases, they are finding records incomplete or falsified.
She says two-thirds of all the cases relating to worker exploitation that the Fair Work Ombudsman has taken to court this financial year have involved record-keeping failures.
Ms James also says, in a pay dispute, any logs of hours kept by workers can be used as evidence, both by the Ombudsman and in court.
"The employer is meant to be doing this. But if they don't have sophisticated time-keeping systems, or, actually, they're deliberately trying to hide exploitation of workers, your own records are really important. So we've always encouraged people to keep their own diaries, and, in the event that we had this and no records from the employer, we would put a great deal of weight in that as we looked to enforce the law."
Matthew Fletcher owns a business called The Food Company that employs 13 workers in manufacturing condiments.
Some larger business have automated time-keepings logs, but many, like Mr Fletcher's, still record the hours manually.
He says he welcomes the new app, and he suggests workers need to be able to protect themselves if there are errors in their pay.
"If there is an error made by us and the employee picks it up, then we're quite happy to retrospectively address that. My concern, the only issue with the app that I see, is, if the employee is recording hours different to the employer and there's a discrepancy, then it's sort of a case of, 'He said, she said.'* Who's in the right? Who's in the wrong? And unless the employer and the employee have a cordial relationship, I just don't know how they will be able to rectify, or come to some sort of agreement."
But Ms James says the app provides more protection to workers in the small number of cases of extreme exploitation.
The app is also available in 12 languages, including Arabic, Chinese, Hindi and Korean.
Ms James says migrant workers often work in the sectors of the economy where exploitation occurs most frequently.
"We know they are vulnerable because of language and cultural barriers. And, certainly, we've been very concerned about workers from migrant backgrounds, who are an increasing component of our work. Thirteen per cent of all of the complaints we had last (financial) year came from visa holders, and visa holders only account for 5 per cent of the workforce, so that is a very disproportionate amount."