The number of school children needing help to speak English has increased by more than 50 percent in the last decade.
Students at May Road School in Auckland's Mt Roskill. Photo: RNZ / Gill Bonnett
Teachers say they were coping without adequate training in some areas and that cash available for extra tuition runs out before some students have become fluent.
Chinese have overtaken Samoans as the largest group of students accessing English as a second language (ESOL) at schools.
Indian, Tongan and Filipino are the most common after that.
Of the 87 schools that have more than 100 students accessing the tuition, 79 are in Auckland, five in Christchurch, two in Hamilton and one in Nelson.
Two schools - Mt Roskill Primary and Southern Cross Campus - have more than 300 students who need government-funded English tuition.
The government funds 41,000 students in more than half of the country's schools in the first two terms this year, the vast majority in Year 1 to Year 8.
That compared to 27,250 students accessing ESOL in 2007.
The Budget earmarked an additional $9.4 million to help meet the growing number of ESOL-funded students over two years.
TESOL Aotearoa New Zealand president Maree Jeurissen said the numbers only showed those who were funded - and that was the tip of the iceberg.
"Many schools, particularly in Auckland ... all of their population would be English-language learners because they all come from migrant backgrounds."
She said such schools would have to use their operations budget to cover other students who used their maximum amount of ESOL or who passed the standard tests in English but were still struggling.
Ms Jeurissen said some students could seem conversationally proficient in English but still not have reached the academic level of language needed to thrive at school.
Immigrant families were also increasingly moving into rural areas where teachers had no experience in teaching ESOL and less access to professional development, she said.
"The reality of what happens often is they just ask an existing teacher to take that role on and that existing teacher may or may not have, but in many cases does not have, particular training."
She said bilingual education should be promoted and funded as it had many benefits to students.
And Ms Jeurissen said more focus was needed on teaching English Language Learners in initial teacher training.
"Every single teacher in our schools, the secondary school science teacher, mathematics teacher, the secondary school history, social studies, drama teacher needs to understand how to learn how to work with English language learners.
"There are some straightforward things which people could start doing tomorrow which would make a huge difference to students."
May Road School has a Samoan bilingual unit. Photo: RNZ / Gill Bonnett
May Road School in the Auckland suburb of Mount Roskill has a Samoan Bilingual unit and about 100 funded ESOL students.
Its acting principal, Beth Noakes, said it has bilingual Samoan classes and celebrated the cultures of its students.
She said funding for English support should last at least until students reached the proficiency needed to learn in classrooms.
The Ministry of Education said schools received $850 a year for a newly-arrived primary school student from overseas and $1250 for a refugee student.
Funding rates were reviewed in 2014 and raised by about 15 percent.
The deputy secretary of Sector Enablement and Support at the Ministry of Education, Katrina Casey, said not all English language learners needed specialist ESOL support.
She said the ministry had no record of the overall number of ESOL teachers.
About 200 teachers a year, including classroom and subject teachers and senior school leaders, receive tuition fees scholarships to study towards a TESSOL (Teaching English in Schools for Speakers of Other Languages) qualification.