But Drew Pavlou, an outspoken critic of the Chinese Communist Party, says there has still been "no real explanation" over why he was removed from the building on Wednesday.

Mr Pavlou was approached by AFP officers at the Queen's Terrace cafe, which is open to the public, as he waited for scheduled meetings with MPs, and told he was considered "high risk" of protesting.

One officer warned the activist he could be deemed a trespasser if he did not comply, raising the prospect of an arrest.

"Unfortunately, it has come down from higher up that they prefer you to leave right now," the officer said.

Mr Pavlou was escorted out by the officers, but returned to the building on Thursday after police confirmed he would not face the same treatment.

Questions had lingered over who ordered the eviction, but an AFP spokesperson conceded "a direction was issued by the AFP security controller at APH".

They had previously refused to answer whether Mr Pavlou would be allowed to re-enter, but on Thursday insisted the incident did not amount to a ban.

The AFP spokesperson claimed the situation changed on Thursday when Mr Pavlou told them he would not launch a protest, despite him repeatedly making that assurance to officers the day prior.

"The AFP has engaged today with the individual, who was clear about his intentions at APH and gave an undertaking about his conduct while at APH," the spokesperson said.

"The individual referred to was not banned from APH yesterday, and was told yesterday he could return closer to his appointment at APH."

Just minutes before he was set to test the AFP's resolve on Thursday, police informed him in a phone call that they would not prevent him from entering.

"I tried to ask what the difference between yesterday and today [is]. Why was I deemed a protest [risk] yesterday, but not today? There was no real explanation," Mr Pavlou told reporters in Parliament's Marble Foyer.

"I think we all know the real reason is simply that all you guys are here with the cameras, and they didn't want the embarrassment of having to try and enforce a stupid trespass order on a member of the public in front of all the media."

Mr Pavlou was in Parliament to meet two senior members of the powerful Parliamentary Joint Committee on Intelligence and Security, Liberal senator James Paterson and Labor MP Peter Khalil.

He was spending time at the cafe in between the meetings, having already sat down with Senator Paterson. He was told he could only re-enter much later, and if escorted by Mr Khalil or his staff.

The activist eventually rescheduled his talk with Mr Khalil on Thursday.

"I'm now marked as a controversial bloke, even though I'm just a peaceful human rights activist, a simple man trying to say genocide is bad," he said.

"The day where I'm literally trying to cause zero trouble at all, keeping my head down [and] suddenly this happens to me."

Mr Pavlou said he was in the building primarily to discuss what he claimed was a targeted harassment campaign by pro-Beijing forces.

A number of bomb threats purportedly from the activist have been emailed to politicians and human rights activists.

He was arrested in London earlier this year after one threat was attributed to him, and said UK police were still considering charging him with sending it.

"I would like to try clear my name, but it's an absolute farce," he said.

"It's the most low sophistication harassment method possible, yet police keep falling for it.

"Maybe they sent bomb threats yesterday to the police, and maybe that's why I got removed from Parliament House."

A spokesperson for the Speaker's Office on Wednesday said the incident did not occur at its request.