Sinn Fein minister dismisses Arlene Foster's misogyny claims as 'nonsense'

"Arlene Foster is trying to divert attention away from getting to the truth and holding those responsible to account," said Mrs O'Neill.

The Health Minister's response to Mrs Foster's sexism claim came as Sinn Fein, the DUP's partners in the power-sharing government in Belfast, rejected proposed terms of a Stormont investigation into a furore that has left the administration facing a £490 million overspend.

Mrs Foster also claimed current health problems being experienced by Sinn Fein Deputy First Minister Martin McGuinness were a factor behind his party's demand for her to step aside, blaming it on internal "jockeying for position".

Mrs Foster went on to state that the DUP was drawing up plans that would wipe out Stormont's Renewable Heat Incentive (RHI) bill.

Alliance Party leader Naomi Long also rejected Mrs Foster's misogyny claims.

"There is misogyny and sexism in politics, just as there is bullying, but it's a dangerous game to misrepresent being held accountable for your actions as any of those things," she said.

Mrs Foster claimed the fact she is the first female to hold the leading position in the Stormont Executive is an issue with many of those demanding she step aside.

"A lot of it is personal, a lot of it sadly is misogynistic as well because I am a female - the first female leader of Northern Ireland - so I firmly believe that is the case as well," she said.

Mrs Foster accused political rivals and social media trolls of misogynistic attacks.

She has been under intense pressure for weeks over her handling of the RHI scandal.

All rival parties at Stormont have demanded she stand aside while her role in the affair is investigated. Mrs Foster oversaw the inception of the RHI scheme during her time as economy minister.

Sinn Fein have warned they will exercise their power to collapse the Executive if Mrs Foster does not temporarily stand down to facilitate a probe.

If the republican party follows through with that threat Northern Ireland will be facing a snap Assembly election, less than a year after the last one.

Again making clear she would not be stepping down, Mrs Foster said the head of Northern Ireland's Civil Service and its Attorney General had drawn up terms of reference for an independent probe into the RHI.

However, Sinn Fein, whose sign-off would be required, rejected the proposed terms of reference as "insufficient".

While not revealing details of the plan, Sinn Fein has insisted any probe must be time-limited and have powers to compel witnesses and subpoena evidence.

The state-funded RHI was supposed to offer a proportion of the cost businesses had to pay to run eco-friendly boilers, but the subsidy tariffs were set too high, and without a cap, so it ended up paying out significantly more than the price of fuel.

This enabled applicants to "burn to earn" - getting free heat and making a profit as they did it.

Claims of widespread abuse include a farmer allegedly set to pocket around £1 million in the next two decades for heating an empty shed.

Highlighting her first-hand experience of violence during the Troubles, Mrs Foster insisted she had been through much worse in her life and made clear she was going nowhere.

"I have come through a lot worse than venomous attacks from my political opponents and I intend to continue to lead," she told Sky News.

"It's no secret that during my childhood the IRA tried to murder my father, it's no secret that in the past the IRA put a bomb on my school bus, so do I really think I am going to step aside at the behest of Sinn Fein? No I am not."

Asked if temporarily leaving her post was preferable to an election, Mrs Foster insisted there was no reason to stand down, as she had "done nothing wrong".

"Simply because I am a woman doesn't mean I am going to roll over to Sinn Fein - I am not going to roll over to Sinn Fein, I am not going to roll over to my political opponents," she said

In a further media interview, Mrs Foster claimed Sinn Fein was in "inner turmoil".

"The Deputy First Minister, Martin McGuinness, is not well and there seems to be some jockeying for position internally," she told the Belfast Telegraph.

"They think this is an opportunity to weaken unionism, but, speaking to ordinary unionists across the province, they tell me we are the party that speaks for them."

It was originally envisaged that the Treasury would foot the bill for the RHI, but the costs spiralled well beyond London's financial commitment.

The total RHI spend in Northern Ireland is estimated at £1,150 million over the next 20 years.

The Treasury is set to cover £660 million of that, with Stormont landed with the remaining £490 million.

The DUP leader has claimed that plans being drawn up by current DUP economy minister Simon Hamilton could clear Stormont's portion of the bill.

"There will be no overspend," she said.

Reacting to Mrs Foster's sexism claims, Mrs O'Neill said: "This is not a gender issue nor is it an Orange and Green issue.

"This is about a financial scandal, which has the potential to cost the public purse hundreds of millions of pounds."

She added: "That is the basis for Sinn Fein calling for Arlene Foster to stand aside, it is not an issue of her gender."

Mrs Foster and DUP deputy leader Nigel Dodds later held talks with Mr McGuinness and Mrs O'Neill.

During the exchanges, Sinn Fein said Mr McGuinness repeated his call for Mrs Foster to step aside, without prejudice, pending a preliminary report of an independent investigation.

Mrs O'Neill said her party had drafted its own proposed terms of reference for a probe.

"These will ensure a robust, time-framed, independent investigation with powers to compel witnesses and subpoena documents," she said.

"This investigation will be led by a judicial figure.

"We have given these terms of reference to the head of the Civil Service and to the DUP."