But it's still stopped short of making masks compulsory nationally, instead leaving it to each school to decide for itself.
That stronger wording comes as the Omicron wave appears to have reached a peak of just over 10,000 daily cases. Covid has killed or hastened the deaths of at least 1252 people in New Zealand, most of them this year.
Daily cases have now dipped below 10,000, but it's unclear how much the school holidays have slowed transmission - and whether cases will rise again when students return to the classroom.
Associate Education Minister Jan Tinetti has now written to school boards, outlining the Government's "strong recommendation to review and enforce a mask-wearing policy as much as practicable", according to a bulletin sent to schools last night.
It said both the Education and Health Ministries were recommending students Year 4 and up should wear masks for the next four weeks, while indoors, where practical and where it won't have a "significant impact on teaching and learning".
That follows Dr Ashley Bloomfield's "strong recommendation" earlier this week that schools bring back mask wearing from Monday.
Schools that had put in place simple measures like mask-wearing were the ones who had been able to minimise infection, he said.
But when questioned on whether the Government should require schools to enforce masking, he said the Ministry of Health had been asked for that advice and had settled on the "very strong recommendation" message.
Under the red light setting, masks were compulsory in schools for years 4 and up, but since the move to orange in April each school board has set its own mask policy.
That's despite strong criticism from public health experts.
The move meant some schools enforced masks while others made them optional or "encouraged" - despite a wave of winter illness causing staff shortages and student absences that forced many schools to return to hybrid or online learning.
Last night's bulletin highlighted those struggles, and said illness was "likely to put more pressure on your school, kura and community".
The public health advice clearly showed masks worked to prevent infection, it said.
It acknowledged some schools may find enforcing masks a challenge, but asked schools to "take action to strengthen your mask-wearing policy as soon as possible".
A letter template had been provided for parents and whanau along with guidance on the benefits of mask-wearing.
There could be situations where masks weren't practical - such as playing indoor sport, singing or drama, or playing musical instruments - in which case ventilation and physical distancing should be prioritised.
"This approach attempts to balance the benefits of mask-wearing with the primary purpose of school's education across curriculum areas and ensure students with particular learning needs that may be hindered by mask-wearing are considered," it said.
The Ministry would later advise whether masking policies should be extended beyond the first four weeks of term.
