Have you ever been asked a question in a job interview that just didn't sit well with you?

Not everything is up for discussion when sitting down for that all-important talk with a prospective employer.

Last week we explained why employers are allowed to employ only non-smokers in their workplace.

Here's a broader look at what prospective employers can and cannot ask you:

Can they ask you your age?

No.

This information should definitely not be asked in an interview.

"If you apply for a job, disclose your age, and are not successful because of this, it may amount to age discrimination if you can prove that age was the reason, or a contributing factor to you not getting the job," Shine Lawyers' employment law expert Christie Toy said.

However, it is important to note that exceptions will apply where a person's age may mean that they are not able to complete the inherent requirements of the role.

"For example, a hotel employer may refuse to hire someone who is under 18 as they would not be able to work with alcohol," Ms Toy said.

"There may be other ways for an employer to get around this question, however, for example by saying, 'This job requires an employee to hold a valid RSA, is this a problem for you?'"

Can they ask if you have children/planning to have kids?

No.

Your prospective employer should not be asking questions about whether you have children or your likelihood of having kids.

Ms Toy says there's a long list of questions prospective employers cannot ask you. ( Supplied: Shine Lawyers )

"If you are treated less favourably than someone else because of having or planning to have children, this may be considered discrimination on the grounds of family responsibilities under the Sex Discrimination Act," Ms Toy said.

Further, a prospective employee has the right under the Fair Work Act, to workplace rights much the same as someone already employed would.

"If an employer is not hiring a female because they may eventually need to give them time off [maternity leave] then this would also be an issue," Ms Toy said.

"Watch out for tricky ways they might ask you this question. For example, 'what are you childcare arrangements?' or 'where do you see yourself in three years?'"

Can they ask your marital status?

No.

Your marital or relationship status should also be irrelevant to any job that you take or apply for and these questions should not be asked.

"It is similarly unlawful to discriminate based on this status and amounts to sex discrimination," Ms Toy said.

This also applies to questions around sexual orientation or gender identity.

Can they ask if you have the right to work in Australia?

Yes.

Employers are allowed to ask whether you are entitled to work in Australia and may require proof of this.

"This, in and of itself is not unlawful," Ms Toy said.

"However, this does not extend to questions around your race or ethnicity, with few exceptions, such as if the role required the person to have cultural connections with Aboriginal or Torres Strait Islander heritage, for example."

Can a prospective employer ask to see your Facebook page?

Chances are they've already seen it before you have even sat down for the interview.

You might want to check the privacy on your Facebook page before you even apply for a job. ( ABC News )

They can ask but there is no requirement to hand over your passwords.

"If you want to control who sees what you get up to on your personal time we recommend everyone checks their social media security settings to better protect their privacy," Ms Toy said.

"It is a good reminder too that many workplaces have social media policies in place and if you bring a business into disrepute with your social activity then there is a possibility you can be terminated."

Can they ask if you have a medical condition?

No.

However, currently many jobs such as those in the police service, or in defence force, may require you to undergo a health assessment due to the requirements of the role.

"This is perfectly lawful and questions around your health may also be permissible in such circumstances," Ms Toy said.

However, employers need to be careful about keeping these questions confined to those that relate to potential health risks in the industry, and your ability to perform the role.

"Questions outside this scope and subsequent discriminatory treatment may amount to disability or impairment discrimination," Ms Toy said.

"For example, if I had diabetes then it would be unlikely this would really relate to my ability to perform the inherent requirements of my role.

"If I didn't get a job on this basis, it would be unlawful."

Can they ask why you left your previous place of employment?

Yes.

An employer is entitled to ask questions about your previous employment.

In fact, they are likely to get some of these answers when your application gets to the reference checking stage.

"Questioning why you left your previous place of employment is lawful as it provides context into why or why not you may be suitable to a role," Ms Toy said.

Can they ask if you follow a religion?

No.

An employer cannot and should not ask whether you follow a religion or a belief, and to do so, and be treated differently as a result, may amount to discrimination on the grounds of religious belief.

You should not be asked about whether you follow a religion or belief. ( ABC News: Sarah Gerathy )

"Once again, this is an area of your life that does or should not affect your ability to complete the inherent requirements of your role," Ms Toy said.

However, there may be some exceptions for religious organisations.

Can they ask if you've ever filed for workers' compensation?

No.

Asking someone whether they have ever filed for workers' comp may be unlawful in a similar vein to asking about medical conditions.

"Discriminating against someone on the basis of them making a previous claim for compensation may be seen as implying that they still have the disability or illness that they claimed for, and may thus amount to disability discrimination," Ms Toy said.

"It also may show that an employee is more likely to stand up for their workplace rights, such as to make a complaint, and breach the Fair Work Act."

Can they ask if you have a criminal record?

It varies, depending where you live.

It is not unlawful under federal law and often depends on the state you are in.

"Many jobs require a criminal history check before offering employment but there are limits on how this information can then be used," Ms Toy said.

"For example, in Tasmania and Northern Territory it is discrimination to refuse to employ someone based on a criminal conviction if this conviction does not affect your ability to carry out the inherent requirements of the role.

"Essentially, the conviction needs to be relevant to the job, for example a conviction for theft may be relevant to a job that requires handling of money.

"Further, a drink-driving offence would unlikely to be relevant to an office worker and their role."

While asking about a criminal record is not unlawful under the federal jurisdiction, the Australian Human Rights Commission can investigate any complaints.

"If the complaint cannot be rectified, the commission may present a report to parliament. This will not necessarily mean that the Act is unlawful and unlike other acts of discrimination couldn't be taken to court," Ms Toy said.

"Employers really need to consider why they would need a criminal record check on the employees they are proposing to hire."

Can they ask if you use drugs or alcohol?

No.

This is largely irrelevant and generally not a question that should be asked in interview.

There are plenty of things a prospective employer should not be asking you. ( Flickr: amtec.us.com )

"Nonetheless, drug or alcohol intake may be relevant to some jobs, for example if you are on medication that affects your ability to drive, this is something that should be disclosed," Ms Toy said.

"Similarly, in a job that requires long-distance driving or operating heavy machinery it may be prudent to ask whether the person takes any medication that may affect their ability to perform this. Many employers have drug and alcohol policies in place that prohibit the use of these substances."

Mandatory drug testing can be part of workplace policies and you may be bound to comply with them.

Can they ask if I'm a member of a union?

No.

It is unlawful under the Fair Work Act, and some states' anti-discrimination legislation, to discriminate against someone based on their trade union activity or affiliation.

"This applies to employees and those seeking employment and is another question to avoid in interviews," Ms Toy said.

"This would also apply to someone who isn't connected to a union but applies for a job in a highly unionised workplace."

What kind of questions should someone expect when going in for an interview?

It should be a combination of technical, behavioural, and cultural questions, employment expert Natasha Hawker, of Employee Matters, says.

"Technical questions are used to determine the skills and qualifications of the candidate," Ms Hawker said.

Ms Hawker says interviewees should prepare responses to likely questions. ( Supplied: Natasha Hawker )

"A behavioural interview question considers behaviours in the past that are likely to indicate the behaviours seen when you put them in a similar position. Past behaviour indicates future performance.

"Cultural questions assess the 'fit' for the cultural of the business, for example, if the business has a strong core value of 'giving back' they will be seeking employees that also follow this philosophy in life."

Ms Hawker said interviewees should prepare for their interviews by thinking of all the questions that they might be asked and also prepare their response.

"This means that they are fluent and well prepared for interviews rather than scrambling for an answer."

So what do you do when you're asked an unlawful question?

This can be a very difficult position to be placed in.

"You don't want to ruin your chances and blow the interview by blatantly asking if the question is relevant," Ms Toy said.

"It may be a good time to, however, reconsider if you really want to work for the employer.

"Perhaps a better way to get out of the situation is to kindly put the interviewer back on track to a more relevant question."

Ms Hawker said her advice was to be "always be professional and respectful".

"I would handle this question in the following way, 'I know that I am going to sound like I am being difficult and you might even wonder whether I am the candidate for you but integrity is important to me, so I need to let you know that asking that question is inappropriate or illegal but this is what I am prepared to share.'"