"Suffrage Day reminds us of all that has been achieved but unfortunately all that there is still to do."
While teachers and principals across the primary and secondary sectors have received pay increases after combined strike action in May this year, support staff are still not fairly paid, Nimmo said.
"We backed the teachers and now they are backing us.
"We have waited a long time for fair pay."
NZEI has now completed an assessment of the role of teacher aides and four comparator groups of male-dominated jobs.
Nimmo spent four months as a member of the team working on the assessment involving 92 interviewees.
"There are so many variations in what teacher aides do and the children they work with.
"The common denominator is that they all work very hard."
Ministry of Education staff worked alongside the NZEI team during the process.
"We took turns and they would take the lead in some interviews while we were the note takers and then we would switch roles for the next one.
"It is the best piece of work that's ever been done on teacher aides' work."
NZEI Te Riu Roa president Lynda Stuart said New Zealand women had come a long way in the 126 years since winning the right to vote, but the persistent pay gap between female-dominated jobs and comparable male-dominated jobs was an injustice that was taking a long time to put right.
"On Suffrage Day we wanted to highlight the incredible work that determined women are doing across many sectors to achieve pay equity."
Stuart said she is optimistic that NZEI can reach a deal with the Ministry of Education by the end of this year.
The roles of teacher aides were measured against four comparator groups of male-dominated jobs - Oranga Tamariki youth workers, Corrections officers, school caretakers and Customs officers.
Work is now under way to set the parameters for pay equity negotiations with government.
The NZEI union is supporting an open letter and petition to the Prime Minister by the Council of Trade Unions, calling on her to make urgent changes to the draft equal pay law.
September 19, 2019, marked the 126th anniversary of New Zealand women becoming the first in the world to win the right to vote.
Whanganui National Council of Women members also joined women from Zonta and the Women's Network for "drinks and conviviality" at the Rutland Hotel to mark Suffrage Day.