Members of the Hackney South and Shoreditch Labour party have voted “overwhelmingly” to support unions’ campaign against the council’s sacking of a shop steward.

Unite bosses have accused Hackney Council of bringing spurious counter-allegations against rep Natasha Johnson – such as “chasing up emails too quickly” and making managers feel harassed by accusing them of harassment.

Natasha was told two weeks ago she would not be getting her job back after being dismissed in November, in the middle of an employment tribunal, after she had already been suspended for a year.

That suspension came while she was going through a disciplinary, and shortly before she was set to appeal over a grievance she had made about “management victimisation, harassment, bullying and racial and sexual discrimination”.

Unite says her treatment highlights the “counter-allegation culture” within the workforce and are now threatening strike action by their hundreds of workers. The town hall “strongly refutes” there is a culture of bullying and racism and has agreed to an independent enquiry on the back of a host of allegations made by Unite, Unison and GMB, which were first revealed by the Gazette in November.

On Thursday night, members of the Labour constituency group went up against the council by voting to support the unions.

A spokesperson said: “As a local party we stand against all forms of bullying, harassment and discrimination and have been particularly troubled by the allegations of such behaviour made against managers in Hackney Council.

“Last night members voted overwhelmingly to support the joint action by Hackney’s Unite, Unison and GMB branches calling for the reopening of the case into Natasha Johnson’s dismissal. We believe the ongoing independent inquiry must address the allegations of a wider culture of institutional racism and bullying within the council and we’ll be writing to the mayor to urge him to take urgent action to address the concerns raised by trade unions and local party members.”

Unite is now planning to bring a second employment tribunal on Natasha’s behalf, this time for unfair dismissal. The results of her first case regarding allegations of racist, sexist and disability discrimination have yet to be announced.

“Natasha is not doing well,” said Unite regional manager Onay Kasab. “As we keep saying, we are dealing with a human being and the impact on her health has not been good.”

Onay is now considering calling a London-wide meeting with union reps from the 32 boroughs about widespread racism, bullying and harassment in local government.

He added: “It’s appalling. The worrying thing is if the council is allowed to get away with making these allegations, in future when people want to complain about bullying or discrimination this is what they will face. We will now be consulting about which areas to ballot for industrial action.”

Hackney mayor Phil Glanville has again stated that all forms of bullying, harassment and racism are unacceptable and will not be tolerated.

He said: “We absolutely refute these claims and I am disappointed Unite continue to make these allegations without coming forward with new and additional evidence.

“The original disciplinary hearing and the appeal followed the council’s disciplinary policy and it would be wrong to comment on this specific case.

“Our work on inclusive recruitment, retention and leadership as well as wider equalities work is extensive and meaningful, with active trade union and staff involvement. We have a cabinet member with direct responsibility for working with trade unions who like me is always open to discussions with them.

“I regularly meet representatives from Hackney Council trade unions about this and other issues and would invite them to direct any new concerns or grievances to me.”