About 700 extra police are arriving in Cairns as the far north Queensland city prepares to host the G20 finance ministers meeting this weekend.

It will be the first major security test since Australia's terror alert status was raised to high last Friday.

Over the next three days about 800 international delegates and 200 media representatives will arrive in Cairns.

From Tuesday, police have additional powers within a declared area of Cairns under the G20 Safety and Security Act.

Police commander Acting Assistant Commissioner Paul Taylor said the declared area ran from Cairns Airport to the CBD.

"The community won't see any visible signs and there'll be no barricades or anything like that," he said.

"The restrictions relate to where the meeting is occurring, which is the Cairns Convention Centre, and also the Transport Department in Kenny Street and the showgrounds.

"These are all locations where either the meetings are occurring or there are activities involved in the operation around the safety and security of the event."

Cairns Hospital health incident controller Brad McCulloch said they had conducted emergency exercises ahead of the G20 gathering.

"We've tested against mass casualty events," he said.

"We've also tested against disease outbreaks, one of the areas we've been very much focused on is the issue of food safety."

'Eggs are good to eat but not to throw'

Acting Assistant Commissioner Taylor said police would have increased powers to stop and search anyone suspected of acting unlawfully.

"There are a number of restricted items, but it's about a person's intent to use those items," he said.

"A classic example probably is eggs — while it's lawful for people to possess eggs if they're obviously using eggs for the purpose of targeting the members of the delegation then that's an unlawful activity."

But he said police were not aware of any planned protests in Cairns.

"We will not tolerate anyone that protests in a way that they create violence or is unlawful," he said.

"But we encourage people that want to undertake peaceful and lawful protests to engage with the police so we can facilitate that."

Grandmother charged over anti-G20 stickers

Police recently charged a Cairns grandmother with distributing anti-G20 stickers after conducting a search of her home.

Myra Gold was charged with wilful damage for posting this anti-G20 sticker in the Cairns CBD. ( Supplied )

Myra Gold, 60, will face court on October 1 for wilful damage of a pole in a public place by placing a sticker on it.

"I was in bed, I think it was about 7:30am and I just heard very loud noises coming down either side of the house," Mrs Gold told 612 ABC Brisbane.

"I said 'what's going on?' They said 'it's the police, it's the police'.

"They introduced themselves to me and gave me a warrant to search the house.

"I've been in this house 30 years — they could have easily looked up and seen that I'm not a terrorist and I haven't got bombs in the backyard."

She said two weeks prior to her home being searched, two people were arrested for writing anti-G20 messages in chalk on the Cairns Esplanade.

Assistant Commissioner Taylor said such actions were unlawful.

"This is the CBD of a city, so if we all went around writing what we wanted to write on the footpath and on walls and sticking stickers everywhere, the place wouldn't look real good," he said.

Homeless people moved out of CBD

Assistant Commissioner Taylor also acknowledged police had been targeting "itinerants" and homeless people in the CBD.

"It's about them competing in public spaces in areas where tourists visit and we've focused on that for some time," he said.

"That’s to make sure the CBD and the business community are able to engage with tourists in a positive way.

"We'll continue to do that through G20 and after G20 goes."

Shirley Pevitt from Anglicare in Cairns said they were prepared for a rise in the number of homeless people needing a bed over the next week or so.

"If we're looking at rough sleepers we're probably talking about approximately 70 in this region," she said.

"That could probably go up to 100 with an event like this coming to town.

"I should imagine we'll probably be at capacity most of that time."