Television ads have started airing ahead of the same-sex marriage postal survey getting underway, but the Government is still waiting to hear from the High Court whether the survey will actually go ahead.

Maybe your mind is already made up and you're just waiting for the ballot to land in your mailbox. Maybe you're not sure how you'll answer the question.

Here are all the ways the survey could still be blocked before it begins.

First the survey has to get past the High Court

The basic point opponents will be arguing is they believe the Government doesn't actually have the power to order this kind of survey.

Within that, there are a couple of points we expect them to focus on:

Whether or not the survey is the Australian Bureau of Statistics collecting statistical data (which is supposed to be its primary function)

Whether or not the survey is the Australian Bureau of Statistics collecting statistical data (which is supposed to be its primary function) If the Government is allowed to spend the $122 million required without the approval of the Parliament

If the Government is allowed to spend the $122 million required without the approval of the Parliament Whether that cash can be spent on seconding Australian Electoral Commission (AEC) staff

FWIW, the Government thinks it's on solid legal footing here.

It's citing a plebiscite run by the ABS decades ago that led to Australia adopting a new national anthem.

The High Court will hear this challenge on September 5 and 6.

If we get past that, the next challenge involves teens having a say

For a hot second, there was confusion over whether 16 and 17-year-olds who are enrolled to vote could take part in the survey.

As the acting Special Minister of State, Mathias Cormann put out a statement clarifying that teens are only "provisionally" enrolled until they turn 18 and the AEC won't be passing their details on to the ABS for the purposes of the survey.

A 17-year-old Victorian schoolboy, Cameron Warasta, has a problem with that.

He's lodged a complaint with the Australian Human Rights Commission, and he told Radio National it's unfair that 16 and 17-year-olds who are on the electoral roll won't be able to have their say.

"Many of us are members of the LGBTI community, many of us are children of LGBTI parents. I think it is only fair that we get a say on this issue," he said.

Here's how that challenge works

Cameron's complaint is based on the fact there isn't any legislation that's been passed through Parliament for the survey to take place.

It's based on some special instructions from the Treasurer instead.

Normally something like this is governed by the Electoral Act, which is exempt from the Age Discrimination Act because you have to be 18 to vote.

Crucially though, that act is not in play for the survey because it's being run by the ABS (not the AEC).

Cameron's case argues the survey is in breach of the Age Discrimination Act because it's treating 16 and 17-year-olds on the roll differently from others.

Daniel Richardson is the spokesman for the complaint:

"We are very confident that instruction is subject to anti-discrimination law and that it cannot unlawfully discriminate against 16 and 17-year-olds who would normally be included in a survey run by the ABS," Mr Richardson told Radio National.

The Guardian reports that group hopes the complaint will be terminated by the Australian Human Rights Commission, allowing them to take the case to the Federal Court.

The plan is for this case to be dealt with just after High Court challenge.

So if the postal survey is going ahead, teens would still have a chance to have their say by the November 7 deadline.