Kate Fisher was sacked by text in June 2011 by Carrie O'Brien, an American who has represented designers such as Georgio Armani, Donna Karan and Chanel.
Ms Fisher took her case to the Employment Relations Authority arguing that although she worked on a "when-required" basis, it was an ongoing arrangement.
Authority member Michael Loftus agreed, concluding "the decision to terminate was a dismissal" so Ms O'Brien was required to justify her decision.
Ms Fisher worked three or four afternoons a week for Ms O'Brien and later took up cleaning duties to earn more money.
According to the authority finding, problems began when the children, now aged 5-13, started complaining "about the way Ms Fisher drove and alleging she swore in their presence".
When questioned, Ms Fisher denied swearing, the finding said. At a later family meeting Ms O'Brien, who is married to Broken Shed vodka co-founder Mark O'Brien, told Ms Fisher it was "scary to speed".
The final straw for Ms O'Brien occurred on June 22, 2011 when Ms Fisher was caring for the five children and three others while the O'Briens went to dinner with friends.
"There was some discord which led to both Ms Fisher and one of the children telephoning Ms O'Brien during dinner expressing their discontent," said the finding.
The next morning Ms O'Brien texted Ms Fisher saying the employment arrangement could not continue because it was too hard.
Mr Loftus found Ms Fisher was unfairly dismissed because her employer didn't attempt to find out what happened or explain the reasons for letting her go.
He ordered Ms O'Brien to pay Ms Fisher $4000 as compensation for humiliation and hurt feelings and $1779 in lost wages.
Ms O'Brien, who is currently signed with the ICAN Model Agency with branches in Queenstown and Dunedin, told APNZ she would not hire another nanny without a written agreement and Ms Fisher was "not qualified" to manage her children.
"It just wasn't working out ... nothing seemed to be going well," she said.
Attempts to contact Ms Fisher through her lawyer yesterday were unsuccessful.
- Abby Gillies of APNZ