"In good faith Event Cinemas gave three months' notice to the staff (we were contractually required to give four weeks) and have provided two weeks' redundancy plus redeployment options," she said.
One person has already been given work at another cinema and six others are negotiating.
The company, owned by Amalgamated Holdings in Australia, took over SkyCity cinemas in 2010 and is the country's biggest cinema chain with 101 screens in 13 locations in Whangarei, Auckland, Hamilton, New Plymouth and Wellington.
Highland Park is the second site to close since the takeover from SkyCity, after one in Hamilton in 2011.
A spokeswoman said the closure today was because competition from nearby cinema centres at Sylvia Park, Botany and Manukau had brought a drop in patronage.
Ms Johnston, who has worked 16 to 20 hours a week since she returned from maternity leave last August, said she had joined the protest to make other people aware of the lack of any legal requirement to pay reasonable redundancy pay.
Unite Union organiser Joe Carolan said New Zealand was one of only a few developed countries that did not have legislation on the issue.