Police are probing the alleged throwing of a homemade bomb into an Invasion Day rally crowd as a “potential terrorist act”.

Thousands of people were evacuated on Monday from Forrest Place in Perth’s city centre after police found an object designed to “explode on impact”.

Police said it was only due to good luck that the device, which allegedly contained a mixture of volatile chemicals with nails and metal ball bearings attached to its exterior, did not explode.

They allege a 31-year-old man removed the explosive device from a bag and threw it into the crowd of 2500 people from a first-floor walkway before trying to run away.

He has been charged with an unlawful act or omission with intent to do harm and making or possessing explosives under suspicious circumstances.

Western Australian Police, Australian Federal Police and the Australian Security Intelligence Organisation have since confirmed they are investigating the incident as a “potential terrorist act”.

In a joint statement on Wednesday night, the WA joint counter terrorism team said its investigation was ongoing and further charged had not been ruled out.

“There is no ongoing threat to public safety,” the bodies said.

It is an offence in Australia to plan or prepare for a terrorist act, with a person still able to be charged with terrorism if it did not occur.

The man did not apply for bail and the case was adjourned until February 17.

The court granted a suppression order of his identity due to fears for his safety.

Indigenous activists had strongly criticised police and political leaders for “double standards” in language after the Bondi Beach massacre was promptly declared a terror attack.

“When violence is linked to Muslims, the word ‘terrorism’ appears in headlines almost immediately,” Victorian Senator Lidia Thorpe said.

“But when First Peoples are targeted … the response is silence, minimisation and delay.”

Prime Minister Anthony Albanese had earlier described the man’s alleged actions as shocking.

“My view … is that they should throw the book at him,” he said in Darwin.

“This was an incident that is quite shocking. He’s been charged with two serious offences and I look forward to him being prosecuted to the full force of the law.”

Rally organiser Fabian Yarran said there had been threats against the event before Monday’s incident.

“The rally had already received several serious threats, yet these were not appropriately addressed due to a lack of police communication,” he said in a social media post.

“This failure placed organisers, participants, and the broader community at risk.”

Yarran was also critical of the police response once the object was discovered, following a tip-off from the public.

-AAP