Both employees were placed under pressure to forgo giving evidence.
Nandni worked at the store between September 2012 and June 2015, but was served a summons on September 30, 2016, requiring her to attend an authority investigation meeting on October 5.
Two days before the meeting, she said a man came to her house telling her not to make trouble with her old employer and said that the Black Power gang had been paid money to threaten her.
On October 4, Kumar also received a phone threat from someone claiming to be a Black Power gang member.
The authority determined that the allegations were of witness intimidation, which was a serious offence.
It found that Neelam, Chirag and Rhythm Ahuja were ultimately responsible for the threats and for attempting to obstruct case proceedings.
"I observe that Ms Nandni and Ms Kumar were very frightened by what occurred, personally and for their families," authority member Eleanor Robinson said.
"It is to their credit that they were prepared to give evidence in the investigation meeting, despite what had occurred."
The decision was made separate to a previous ERA determination that the directors be personally liable for $68,783 in unpaid wages and holiday pay owed by their companies Khoobsurat Collections Ltd/Naari Collection Ltd.
Both decisions were ordered prior to the end of 2016 after the Indian retail clothing stores went into liquidation.
"This decision relates to an action brought by the Authority on its own motion and also sends a strong message the Labour Inspectorate will not tolerate intimidation," Labour Inspectorate Regional Manager Loua Ward said.
"Safety is paramount and witnesses need to feel confident in coming forward so that the Labour Inspectorate can take action against unscrupulous employers who continue to take advantage of workers."
Ward said it was in public interest that the penalties served not only to punish employers who attempt to obstruct judicial processes, but also as a deterrent.
The Ministry of Business, Innovation and Employment is encouraging anyone in this situation, or who knows of anyone in this situation, to call its contact centre on 0800 20 90 20.