Labour Party leader Andrew Little says it is likely that cleaning and catering company Spotless will get rid of zero-hour contracts for Parliamentary staff.
The Labour Party was urging the Speaker, David Carter, to stop a contractor employing workers at Parliament on zero-hour contracts.
Mr Little said Mr Carter had confirmed nine staff were employed on the contracts under which they were guaranteed no work but had to be available at any time.
Mr Little said zero hour contracts were unnecessary and workers could easily be on casual or part-time employment arrangements.
A spokesperson for the Parliamentary Service said its contractor was looking at all nine zero hour contracts and will work to have guaranteed hours for those workers.
Mr Little said he understood the contractor was Australian cleaning and catering company Spotless.
He said the practice was going on under the nose of Workplace Relations Minister Michael Woodhouse, who had said he would outlaw it.
Mr Little said while the employment practice was used by a contractor, the Parliamentary Service had to step in.
"They run the contract. They are the principal in the contract. They can actually intervene, go into that contract, say to the contractor 'we don't want this style of employment here'. And that is the least they should be doing."
He said he would raise the matter in a meeting with Mr Carter tonight.
Prime Minister John Key said he was not sure if the workers really were employed under zero-hour contracts.
"I think they're called something different. You'd need to check but it's a matter for parliamentary services. But there's certainly a place in the workplace for flexibility I think in terms of contracting."
Mr Key said it was not acceptable, however, for employers to tie a worker exclusively to their employment with no guarantee of work.