Pauline Hanson has pledged to abolish the National Indigenous Australians Agency (NIAA) if One Nation forms government, using a combative National Press Club address to defend the party's policies on Indigenous affairs, multiculturalism and public broadcasting.

As One Nation has risen in opinion polls, the far-right party has come under increasing scrutiny. On Wednesday, Senator Hanson faced journalists in Canberra, delivering what was at times an aggressive and angry speech as she defended her reputation and advocated her party as one ready for future government.

One Nation has previously indicated its policy platform includes abolishing the NIAA and the Therapeutic Goods Administration (TGA), arguing the moves would reduce government debt and ensure First Nations people are treated the same as other Australians.

Senator Hanson claimed a First Nations child should not receive greater education funding than another child, telling the Press Club her vision for the country is that "we're all Australians, regardless of race".

Asked by NITV reporter John Paul Janke where funding earmarked for the NIAA would be redirected and what support would remain for Indigenous people living in remote and rural areas if departmental programs were removed, Senator Hanson said: "That money will go into consolidated revenue, where any Australian can get that help if they need help."

"And all this money that we've paid out — probably about $30 billion plus a year — where has it begun?" she asked.

"Where is the accountability? Where has the gap been closed?"

Senator Hanson did not identify the source of the $30 billion figure, saying only that it was the amount she advocated for.

The figure, which is frequently cited by conservative commentators, was first publicly raised by Warren Mundine in 2016 while appearing on ABC's Q&A program.

A 2016 fact check by the Australian National University found only $5.6 billion, or 18.6 per cent of total expenditure, was directed to Indigenous-specific programs.

The remainder, it said, "comprises the cost of providing mainstream services, such as schooling and health care, that all Australians enjoy".

Senator Hanson — who has regularly been accused of racism and was found to have breached section 18C of the Racial Discrimination Act — also said she would not begin her speech with a "divisive" Welcome to Country.

A Welcome to Country is delivered by an Aboriginal or Torres Strait Islander Traditional Owner or Elder — something Senator Hanson is not.

It differs from an Acknowledgment of Country, which can be delivered by anyone and recognises the Traditional Custodians of the land on which an event is held.

Attack on multiculturalism and public broadcasting

The One Nation leader used her address to argue her well-worn comments that Australia is "losing its identity", describing multiculturalism as a "failed policy".

Citing public concerns over immigration and housing, she rejected claims that her opposition to all cultures being afforded equal prominence was racist, instead lambasting people from Muslim backgrounds.

"We cannot be a multicultural society," she said.

"We are a multiracial society, but we must be monocultural. Australians must live under the one cultural umbrella."

The Senator, who at times appeared visibly agitated at journalists — at one point calling Guardian journalist Sarah Martin "trashy" and claiming she had an "obsession" with her — also outlined plans to significantly reduce public broadcasting, a stance long-agitated by conservatives.

She told SBS chief political correspondent journalist Anna Henderson under a One Nation government, "You're going to be without a job, certainly."

"There will be big changes if One Nation is given the chance," she said.

"The SBS will be gone. There's no need for it anymore; the internet has overtaken the need for it.

"The ABC will still exist, but in a very different form. Taxpayers will still fund some of the ABC's operations in regional, rural, and remote areas where there is a lack of commercial media. But in the cities — which are already saturated with media outlets across the political spectrum — the ABC will only be a subscription service."