Further strike action's on the cards as primary school teachers and principals overwhelmingly rejected the Government's latest collective agreement on Monday.
Union members will now vote on taking industrial action, with the possibility of a mega-strike alongside secondary school teachers being considered.
Primary School teachers and principals took strike action late last year, and may soon leave the classroom again for a day of protest.
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"Significant disruption could occur in schools next term if the Government doesn't focus on finding a solution very quickly," said New Zealand Educational Industry President Lynda Stuart.
That's a solution to a year-long dispute over pay and staffing which affects members like Sose Annandale, the principal of Porirua's Russel School, who on Monday was unable to find relievers for two sick teachers.
"I'm nervous because we haven't even hit winter, and flu season," she said.
The latest offer was similar to the one rejected in November - but gave teachers two additional options: either a new salary step brought forward to February 2020, or more classroom release time for tasks such as planning.
Stuart says the offers fell short.
Union President Linda Stuart says the Government needs to increase its overall package of $698 million, but the Education Ministry says it won't budge.
If there's no progress by next month, union members will vote on a national day of strike action for May 29, and 'partial strike action' from May 15 by 'working to rule' - which means no work after 5pm.
Among those supporting them are secondary school teachers, who are also involved in pay talks. A mega-strike involving teachers across both levels is on the cards.