A former aide to Priti Patel received a £25,000 payout from the government after claiming she was bullied by the then employment minister.
Legal correspondence seen by the BBC alleges the woman took an overdose of prescription medicine following the alleged incident in 2015.
The DWP did not admit liability and the case did not come before a tribunal.
Ms Patel is facing allegations - which she denies - that she mistreated staff in her current role as home secretary.
Sir Philip Rutnam, the Home Office's most senior official, resigned on Saturday alleging Ms Patel's conduct towards staff included "swearing, belittling people, making unreasonable and repeated demands".
He said he now intended to take legal action against the Home Office on the basis of constructive dismissal, alleging that he had been forced out of his job.
'Robust and determined'
The government said on Monday, before the latest allegations, that the Cabinet Office would investigate whether Ms Patel has breached the ministerial code and to "establish the facts".
Labour's shadow home secretary Diane Abbott has now called on Ms Patel to step down from her role while the investigation takes place.
She told BBC Radio 4's Today programme: "We want a genuinely independent inquiry. A lawyer-led inquiry and something that can seen to be independent.
"I'm afraid it would be better if she stepped down. We are calling on her to step down whilst the inquiry goes on."
Health Secretary Matt Hancock declined to comment on the allegations of bullying against the home secretary because of the ongoing investigation and "potential legal action".
But he added: "I know Priti well and she is robust and she is determined and that is what you would expect with a home secretary.
"She is also extremely courteous and kind."
Legal correspondence seen by the BBC show a junior employee at the DWP brought a formal complaint of bullying and harassment against the department, including Ms Patel, after being dismissed from her role in October 2015.
The staff member's grievance letter alleges she had previously attempted to kill herself after reporting similar allegations of workplace bullying concerning another individual in 2014, before Ms Patel was a minister.
The staff member also alleges she was told the decision to dismiss her a year later was not made on performance grounds but because Ms Patel did not "like [her] face", according to comments attributed to her line manager and a colleague.
On that day in October 2015, Ms Patel had shouted at the woman in her private office and told her to "get lost" and "get out of her face", the correspondence alleges.
Ms Patel is described as having acted "without warning" and with an "unprovoked level of aggression", in the woman's formal grievance complaint.
Shortly after, the staff member allegedly took an overdose of prescription medication in the office and lay with her head on the desk for some time.
She was then said to have become unresponsive and her partner was called by a colleague to collect her as she was unable to walk unaided.
The woman then took a further overdose at home in what is described as an attempt to kill herself and was rushed to hospital where she spent the night in resuscitation, according to the documents.
Priti Patel's career as an MP
- First elected as Witham MP in 2010
- Became Treasury minister in 2014 and minister for employment in 2015
- Appointed secretary of state for international development in July 2016
- Resigned from the role in 2017 after it emerged she had held undisclosed meetings with Israeli officials while on holiday
- Appointed home secretary in July 2019, a post she still holds
A settlement was reached in 2017 for £25,000 after the member of staff threatened to bring a legal claim of bullying, harassment and discrimination on the grounds of race and disability against the department, including Ms Patel who is directly named.
When asked last week about a complaint against Ms Patel during her time at the DWP, a source close to her said she was "unaware of any complaint being made".
Prime Minister Boris Johnson backed Priti Patel following Sir Philip's allegations, saying she was "a fantastic home secretary".
On Monday, before the latest allegations emerged, Cabinet Office minister Michael Gove told MPs Ms Patel "absolutely rejects these allegations".
But he said the prime minister had asked the Cabinet Office to carry out an investigation into whether she had breached the ministerial code and "to establish the facts".
Labour MP Hilary Benn asked Mr Gove if any complaints had been made about Ms Patel's conduct at the DWP, or in her former role as international development secretary.
Mr Gove said: "The inquiry that is proceeding will look at all complaints that may have been made, I cannot say more than that."
A spokesperson for the government said "All ministers are subject to the ministerial code. We do not comment on individual personnel matters."
Asked by Labour's Yvette Cooper how many complaints had been made against Ms Patel, Mr Gove said it would be "improper" to comment on an "individual personnel case".