About 70 cleaners and supporters gathered outside Parliament on Wednesday afternoon, chanting and banging buckets to protest against proposed changes to employment law.
The Service and Food Workers Union delivered more than 2000 submissions opposing changes to the Employment Relations Act.
At present, if a business is restructured or sold the new employer must retain staff under contract such as cleaners or caterers.
The Government wants to exempt businesses with fewer than 20 staff.
The Service and Food Workers Union says that would allow cowboy contractors to drive down wages to win contracts.
A parliamentary cleaner, Mareta Sinoti, told the protest group the current law was the only job security some workers had.
However Labour Minister Simon Bridges said the changes would help provide more certainty for businesses while retaining key benefits for employees.
