And of that number, 47 per cent said the time taken for NCEA assessments affected their teaching.
Among decile nine and 10 schools, barriers tended to be NCEA related.
In those schools, 55 per cent of teachers said time spent on assessments was problematic, compared with 39 per cent for teachers in decile one and two schools.
NCEA requirements were a barrier for 47 per cent of teachers in decile nine and 10 schools, compared with 34 per cent for deciles one and two. The impact of parents' expectations was a concern for 12 per cent of teachers in high decile schools, but fell to five per cent in low deciles.
Sandy Pasley, Secondary Principals' Association of New Zealand president, and principal of Auckland state-integrated decile nine school Baradene College, said students need to do more external achievement standards.
She said the current system impacted on teachers' workloads, due to a heavy focus on internal assessment.
"Teachers have to spend a long time ensuring that the moderation is rigorous and that marking systems are fair. It all takes time to organise."
The internal load had increased over the past few years, and system changes needed to be made to combat the increase, Ms Pasley said.
She said changes needed to be mandated at a national level, so all schools were on the same page.
"Unless everybody's doing it, you won't get effective change."
She said expectations to achieve were high among pupils of high decile schools, because they wanted to do well, which was laudable.
"And schools want to see their students achieve their potential so that they've got wide options when they leave school and so they're not narrowed to careers they don't want."
The NZCER report's co-author, Dr Cathy Wylie, said the pressure on students in higher decile schools came from parents, teachers and schools, as well as students.
"It's the pressure to get merits and endorsements to really ratchet up what you can put on your CV. And with high level of competition between secondary schools. It all adds up."
Dr Wylie questioned whether the NCEA system was too fixated on assessment.
"And what that might be doing is actually thinning out the curriculum."
She said to combat the problem, work needed to be done at both a national and at a school level.
The Ministry of Education's deputy secretary for early learning and student achievement, Lisa Rodgers, said the findings showed support for NCEA was stable.
"Fewer teachers reported workload concerns in this survey than the 2012 survey."
Ms Rodgers said the Ministry continued to work with the sector where there were ongoing challenges.
"An example of that is our work with the Workload Advisory Group, whose membership includes Ministry of Education, NZQA, teachers, principals and PPTA. The group has already made recommendations which have led to changes, including the provision of two days allocated in each of 2011, 2012, and 2013 for teachers to work on NCEA assessment." She said the group would report to the Minister of Education in December on any concerns about secondary teacher workload.
