Barnaby Joyce has voiced serious security concerns after Pauline Hanson’s appearance at the National Press Club was interrupted by a banner that dropped down during her speech.

“What if it had been a bomb?” he asked.

GetUp! has taken responsibility for the action. The banner showed Ms Hanson alongside the words: “I opposed a pay rise for workers when I took a $100,000 pay rise for myself”.

David Sharaz, Brittany Higgins’ partner, was at the event and was seen recording the moment the banner unfurled before leaving soon after.

CCTV revelations suggesting two unidentified people entered the National Press Club on Tuesday to install the display without staff knowledge have prompted an Australian Federal Police investigation.

“It’s so dangerous when you think about it,’’ Barnaby Joyce told the Karl Stefanovic show.

“So they go in there, they managed to break up a sign, and then have the capacity to lower it. Ha ha, very funny?

“If you have capacity to do that, first thing that goes through your head is what if that was the prime minister, and down came a bomb?”

“How did they get there? How did that happen? And we now have to take precautions, because the baddies will see that and go, ‘that’s interesting’.”

Mr Joyce said he believed the stunt was an “inside job”.

“(Ms Hanson) had to deal with a curveball that no one else had to deal with, that nutcase sort of charade,” he said.

“It looked like amateur hour. I hope they find the person, someone obviously knows how to operate it. It’s an inside job. Find the person, kick their a**e, kick their a**e hard.”

The National Press Club said no staff or contractors were involved.

“No Club personnel or Club contractors had any involvement in this matter,” the NPC said in a statement.

“We have referred the relevant footage and other evidence to the AFP for further investigation.

“The organisation GetUp! is claiming credit for the stunt. The GetUp! representative at the address was David Sharaz.

“At time of writing, we understand he is yet to be interviewed by the AFP.

“It appears that two persons entered the Club building (on Tuesday) afternoon without permission and installed a separate drop-down screen in front of our media wall/light box.

“It is evident that a further person present during the address activated a remote device to trigger the unfurling of the coiled banner.

“David Sharaz was seen filming the incident on his phone and, after the banner had lowered, left abruptly.

“We understand that this is likely to form part of the AFP investigation.”

The club said it would “consider its legal options” against those responsible, including seeking to recover costs linked to major damage to the media wall and light box.

“The Club sincerely apologises to Senator Hanson for the incident,” the statement reads.

GetUp! openly acknowledged it organised the protest.

“It was us,’’ the group said in a statement.

“Pauline Hanson has built her entire brand on being for the battlers. But her record tells a different story. One Nation has consistently opposed wage rises, affordable childcare, increases to the aged pension, and housing affordability measures,’’ GetUp! CEO Paul Ferris said.

“We thought the occasion deserved some honesty. So we provided it.”

In her speech, Ms Hanson said Australians were “eating out of rubbish bins” and that children were arriving at school hungry. She also pledged to abolish SBS, make the ABC a subscriber-only service in the cities, and remove the Sex Discrimination Commissioner.

Rejecting accusations of racism, Senator Hanson said she had remained consistent while other parties had moved toward her position. She accused Prime Minister Anthony Albanese of “lies” on tax reform.

“And that’s why my policy to slash immigration reflects what most Australians want,’’ she said.

“The story is simple. My views haven’t changed. Other political parties are simply following me.

“Because that’s what most Australians want. Especially after Bondi and the return of ISIS brides.”

She described Australia’s immigration policy as being in “a state of crisis”, blamed migrants for worsening the housing crisis, and said people were heading to bed earlier to cut electricity use.

“How can we as members of parliament who are supposed to represent the people of this nation allow that to happen?’’ she said.

“It is disgraceful. And yet this Albanese Labor government cannot help our own people here but keeps bringing more people into the country, flooding it time and time and time again.

“At the centre of this crisis is the utterly flawed policy of multiculturalism. We cannot be a multicultural society. We are a multiracial society, but we must be monocultural. Australians must live under the one cultural umbrella.”

The event also featured a tense exchange with Guardian reporter Sarah Martin during question time. Ms Martin asked about Lee Hanson, Senator Hanson’s daughter, working for a NSW MP while living in Tasmania, where she is campaigning.

“Taxpayers are paying more than $150,000 a year for your daughter, Lee Hanson, to seemingly (be) campaigning full-time in Tasmania, while employed as a political adviser for a NSW senator,” Ms Martin asked.

“Did you have any role in appointing her to that position?”

Senator Hanson rejected the basis of the question and launched a personal attack on the reporter.

“Honestly, you never give up. I’ve never seen a person who is such a trashy journalist,” she said.

“You’ve got this obsession with constantly trying to pull down myself, my party or Mrs Rinehart, whatever you do.

“You will be banned. I’ll answer you this question today, but I’m telling you now, don’t come near me for an interview in the future.

“You don’t research properly, you don’t know your information, and you will put out lies about me.

“Well, I’ve had enough of that. But I’ll tell you that, no, she didn’t, I didn’t get her that job.

“She got the job on her own merits by someone who actually wanted to employ her, her abilities, her skills in HR, her abilities in working for the Tasmanian university for eight years and was head of a department down there.

“So my daughter is very capable. She might end up in the Senate with me.

“If I’m fortunate enough to get elected by the people of Queensland, you’re going to have a lot to write about then, aren’t you?”

Senator Hanson also used the speech to compare “transgender ideology” with radical Islam, while saying she did not object to transgender people personally. She argued they should not be allowed in female change rooms.

“Just because you lop off your penis and put on a dress does not make you a woman,” she said, quoting Germaine Greer.

“This movement, like radical Islam, is everywhere.

“I am simply saying that a transgender woman should not be allowed into women’s sport or into a women’s changing room. And likewise, a transgender man.”