Here's what happened in the Voice to Parliament referendum campaign trail this week

An estimated 200,000 of people marched in Walk for Yes rallies around Australia last Sunday.

The official "yes" campaign also launched a $20 million advertising campaign, featuring a young Indigenous boy asking if he will "grow up in a country that hears my voice".

Meanwhile, "no" campaigners gathered at an event on Monday evening in Adelaide - one of the key battleground states - where Warren Mundine told attendees that First Nations people have "always had voices".

"Australia is not a racist country and our people are not racist," he said.

Legendary Olympian Cathy Freeman came out in support of the Voice this week, saying she couldn't "remember a time when change has felt so urgent, where momentum has been so strong".

"We have the chance to be part of a moment that brings people together, to work hard for something that we can all believe in and right now each of us can be part of something that really matters," Ms Freeman said in a "yes" campaign video.

But she wasn't the only high-profile figure to lend her voice to the campaign.

US rapper MC Hammer - yes, the guy behind the hit song U Can't Touch This - expressed his support via Twitter on Thursday night, saying he got "up to speed" on the issue, after being tagged in a post.

"Australia it's time. Repair the breach," he posted.

United Australia Party founder Clive Palmer, along with current federal senator Ralph Babet, lost their court bid to get crosses to count as "no" votes on referendum ballot papers.

To be clear: the ballot paper will explicitly ask you to vote either "yes" or "no" to the referendum question.

But the Australian Electoral Commission also follows longstanding (i.e. decades-long) legal advice that ticks can broadly be accepted as a "yes" vote in a referendum, but a cross is considered too ambiguous.

Mr Palmer and Mr Babet unsuccessfully challenged the AEC on the matter in federal court.

On Wednesday, Justice Steven Rares ruled in favour of the agency, explaining that a cross could be intended to express agreement, disapproval, or even an unwillingness to answer the question altogether.

The AEC revealed that a mammoth 97.7 per cent of eligible Australians have enrolled to vote ahead of the referendum, the highest enrolment rate since federation.

With the deadline for enrolment having closed last Monday, the AEC now has 17,676,347 Australians on the electoral roll. This includes a record enrolment rate for young voters aged 18-24 (91.4 per cent) and Indigenous peoples (94.1 per cent).

Speaking of the electoral commission, the AEC said it is seeing more threats against staff in the lead up to the referendum than during any other electoral event.

Commissioner Tom Rogers said the agency is also seeing higher levels of online "vitrol" and "tinfoil hat-wearing bonkers mad conspiracy theories".

He said that social media platforms weren't responding to requests to take down misleading posts. Out of 47 referendum-related social media items that the commission referred to platforms, Mr Rogers said only 16 had been acted on.

The commissioner said there had been a "reduction in platforms' overall willingness to act".

"We've had a few things over the last couple of weeks that have effectively been veiled threats of violence to staff," he said.

"We've referred those to platforms and almost universally they've come back and said that doesn't breach their standard."

The official "no" campaign had to distance itself from anti-Voice demonstrations this weekend that were purportedly organised by Simeon Boikov, an online commentator who posts pro-Putin content.

Opposition leader Peter Dutton urged those against the Voice to avoid attending the rallies.

"Anybody who's pro-Putin has significant issues and they should seek help for those issues," Mr Dutton said.