New Zealand school teachers went on strike on Wednesday for the first time in more than 20 years, challenging the Labor government’s plans to balance promised fiscal responsibility against growing demands to increase public sector salaries.

The government’s first budget in May was stretched to fulfill its promise to juggle investing in much-needed infrastructure with a self-imposed rule to pay down debt and insulate the economy from potential shocks.

Almost 30,000 primary school teachers did not turn up to work on Wednesday and held protests across the country, leaving parents of children aged 5 to 13 at public schools scrambling to find childcare.

“Teachers and principals voted for a full day strike…to send a strong message to the Government that the current collective agreement offers from the Ministry of Education would not fix the crisis in teaching,” said Louise Green, lead negotiator at NZEI, the union that represents teachers, in a statement.

NZEI said it has asked for a 16 percent pay increase for teachers over two years, whereas the government has offered between 6.1 and 14.7 percent pay rises, depending on experience, over three years.

“Our view is that we need to have those discussions around the negotiating table but…there isn’t an endless amount that we have available to us in order to meet those expectations,” Prime Minister Jacinda Ardern said at her weekly news conference on Monday.

​The action comes in the wake of a one-day nationwide nurses’ strike in July and a series of smaller actions by government workers, challenging Ardern’s center-left government, which ended almost a decade of center-right National Party rule in October.

The stand-off with its traditional union support base comes nine months after Labor formed a coalition government, promising to pour money into social services and rein in inequality, which has increased despite years of strong growth.

Wage growth has remained sluggish in the island nation for years, despite soaring housing costs, which labour groups and economists say has left workers struggling despite robust growth.

The government is also struggling with gloomy business confidence, which has sunk to decade lows and contributed to a surprise signal from the central bank on Thursday that it planned to keep rates on hold into 2020 and saw downside risks to its growth forecasts.