Magistrates extended the notice against Crystal bar that was requested by South Yorkshire Police during a hearing held at Sheffield Magistrates' Court held this afternoon.
Two men were rushed to hospital with life-threatening injuries, and a further four were left with superficial stab or slash wounds following the violent incident at the bar on Carver Street at around 2.20am on January 1, 2018.
All six men are from the Birmingham area.
Representing South Yorkshire Police, James Kettering, said: "We're very close to reaching an agreement with Crystal, but haven't reached that point yet."
He added: "If that is not possible we will call on the local authority for assistance."
Sheffield District Commander, Chief Superintendent Shaun Morley, confirmed last week that police believe the altercation to be 'gang-related,' based on the evidence collected by detectives so far.
Describing the brawl to magistrates, Mr Kettering added: "There's the possibility of a knife being used. It appears that glassware was also used."
Christopher Grunert, representing Crystal, confirmed the bar would not be opposing the request to extend the closure notice.
"These are unprecedented circumstances which require unprecedented action," said Mr Grunert, adding: "We intend to work with the police to come to an agreement."
South Yorkshire Police initially said that there were five victims but have now revealed that there were six men either stabbed or slashed 'as a result of an altercation believed to have taken place at the top of a flight of stairs'.
Two of the men, aged 22 and 20, were left fighting for life after the attack and remain in hospital in a serious but stable condition.
No arrests have been made in connection with the brawl, a police spokesman confirmed today.
Chf Supt Morley added: "Sheffield remains a safe city. It has traditionally and historically been viewed this way and we will maintain that. Incidents like this will not be tolerated and we will leave no stone unturned until we identify and arrest those responsible.
"We have proactive and enforcement operations in place to address this issue and those individuals who carry knives."
This comes after District Judge, Naomi Redhouse, granted a 28-day closure order for the Niche nightclub, during a hearing at Sheffield Magistrates' Court this morning.
The club has been closed since December 23, when four men were stabbed and another was injured during a violent altercation in the Wicker area of the city.