With debate continuing in federal Parliament and around the country, the Australian Bureau of Statistics is aiming to distribute 16 million survey forms in a staggered mail out by September 25.

Last week the High Court ruled the survey could go ahead and federal Parliament is expected to pass legislation to increase legal protections for the process.

Here's what you need to know about participation in the non-compulsory survey:

When will I receive my survey form?

Survey forms are expected to be received at addresses registered with the Australian Electoral Commission by September 25.

Forms going to areas with less frequent mail service will be posted first, using priority postage.

If you do not receive the form and instructions by September 25, you should contact the Australian Bureau of Statistics.

From September 25, Australians will be able to register to take part in the survey by telephone and online if they cannot complete a paper survey form.

Australians living overseas or in remote locations can complete the survey online or by phone, using a unique 16-digit secure access code. Forms will also be available for in-person collection in capital cities and regional locations.

Requests for replacement forms will be accepted between September 25 and 6pm October 20.

Australian Defence Force members on deployment or Australians posted in the Antarctic will receive advice from their employers on how to participate.

People experiencing homelessness will be able to pick up a form in-person until October 20.

How do I fill in the form?

The form asks, "Should the law be changed to allow same-sex couples to marry", and has 'yes' and 'no' boxes to be marked by the voter.

Use a dark pen to mark your response.

It must be returned in a reply paid envelope.

The ABS has discouraged participants from marking the form in any way other than responding to the question. Graffiti or messages could make it difficult for survey responses to be read.

A response may not be valid if both boxes are marked or the printed barcode on the form is missing or altered.

Instructions on completing the form will be included in 15 languages.

Can someone fill in the form for me?

If you cannot access or complete your survey form, you can authorise a so-called "trusted person" to complete the survey on your behalf.

The designated trusted person can be a friend, family member or another person you trust.

There is no formal process to appoint a trusted person. The ABS describes it as a private arrangement between the eligible Australian and the person they ask for assistance.

Participants should tell their trusted person how to respond to the survey for them.

What if I am moving house or travelling during the survey?

If you won't be at your enrolled address during the mail out period, you can arrange to have your mail forwarded, ask a trusted person to complete it on your behalf, or contact the Australian Marriage Law Postal Survey Information Line.

You can also use an online form to arrange for your form to be sent to a different address.

Can I get a new form if it is lost or damaged?

If you need a new form, you can request one between September 25 and and 6pm on October 20.

When do forms have to be returned by?

Australians are encouraged to return their survey forms by October 27.

The ABS will close receipt of forms at 6pm on November 7. Forms returned after this date won't be counted.

What if I don't want to participate in the survey?

People choosing not to participate are encouraged to destroy their form.

When will the results be announced?

The ABS will announce the result online at 11.30am on November 15.

The results will be broken down by federal electorates, state results and a national result.

What role does Australia Post have in the survey?

An Australia Post spokeswoman said it had the ability to distribute and return the survey forms without additional resources.

"Given our expertise in delivering more than 2.5 billion items across our network each year, or about 12 million items a day, we have both the capability and the capacity to deliver the expected 16 million surveys to the highest service levels.

"Australia Post has robust security measures in place throughout our national network and ahead of delivering the survey, have added additional measures in place for the duration of the process.

"We are also working closely with the authorities to maintain the integrity of the mail network," the spokeswoman said.