The government has proposed changes to sick leave rules, which could mean that part-time workers are entitled to less.

Here's what you need to know about the rules now, and how the proposed changes might work.

What are the current rules?

At the moment everyone, including part-time and casual employees, is entitled to 10 days' sick leave a year, if they have been working for their employer consistently for six months and have worked an average ten hours a week, and at least one hour in every week or 40 hours in every month.

Every year after that, they are entitled to another 10 days' sick leave. Under the Holidays Act, the number of days' leave that can be accumulated is capped at 20 but employers and employees can negotiate for this to be higher.

Unless it's in your employment agreement, sick leave is not paid out when you leave a job.

What counts as a sick "day"?

The Holidays Act talks about days, rather than hours.

If you work for part of the day and then go home sick, this could potentially be counted as a whole day of sick leave.

Employers and employees can agree to describe the sick leave entitlement in hours or part-days if that is better.

Why do part-time workers get the same number of days of sick leave?

Employer advocates have argued that it is unfair that someone who works one ten-hour day per week could, in theory, have ten weeks' worth of sick pay under the current rules.

But NZ Council of Trade Unions policy director and chief economist Craig Renney says it was not fair to say that part-time workers were getting more.

Sick leave is only paid for the hours normally worked, so part-time workers get less if they do not normally work full days - and even in the scenario where someone worked one day a week, would only be being paid for the one day.

"If they work four hours in a work day they only get sick leave for those four hours - not eight as some would have you believe. It's about the opportunity to access sick leave."

He says sickness "doesn't discriminate" between types of workers.

What's being proposed?

Workplace Relations Minister Brooke van Velden has proposed making sick leave entitlements proportional to the hours someone works.

"Workplaces that rely on part-time workers are particularly vulnerable to unexpected staffing shortages. To explore this issue further, the exposure draft set for consultation will include a proposed approach to pro-rating sick leave, to better reflect how much an employee works," she says.

What does pro-rata mean?

Pro-rata is a term used to describe a proportionate allocation. You often hear of it when someone is on part-time wages and their salary is the pro-rata equivalent of a certain percentage of the full-time wage.

In this case, it could mean that a part-time worker would get a percentage of the full sick leave entitlement based on how many hours or days they worked.

Do you really get twice the sick leave if you have two part-time jobs?

"An employee's leave entitlements apply to each job they have. So if you have two part-time jobs, you will be entitled to sick leave - and annual holidays - for both of those jobs.

"Remember though that sick leave is usually paid at your relevant daily pay - the pay you would have got, had you worked on that day.

"So if I work at one job on a Tuesday morning, and one job on Tuesday afternoon, but I'm sick on Tuesday - and I meet the entitlement criteria for sick leave - I'll take a day of sick leave and be paid my relevant daily pay for job one, and a day of sick leave and receive my relevant daily pay for job two - you wouldn't be doubling your pay for that day."