There have been tears and anger in New South Wales schools after year 12 religion students were left stumped by a question in their final exam.

McAuley Catholic College student Lauren Priest says the final extended response question on the HSC exam was not based on anything they had studied in their curriculum.

"We were like, there's a question in there that has got nothing to do with what we learnt, and everyone flicks to see the extended response, because that's a big question and that's the one that was written wrong," she said.

"We were trying to explain to them what it was about because they obviously don't know what the syllabus is, the supervisors, and it took a while for them to get around their heads, and for us to kind of calm down.

"So we didn't start for like half an hour after the start of the exam had started."

She says the question began with a quote and then asked students to assess, in relation to the quote, how Christianity is a living religious tradition in the life of its adherents.

The HSC exam is worth 50 per cent of a student's final mark.

Ms Priest says it was a nightmare situation for students.

"Half the year started to cry in there because it was so overwhelming that we'd prepared so hard for something and then get in there for something that you can't answer, it's like a nightmare," she said.

"And so everyone was angry and I think some people didn't actually even attempt the question."

But the NSW Education Board's chief executive Carol Taylor is adamant the question was based on the syllabus.

"I'm confident that the questions in the examination paper are all directly from the syllabus, it's just that this year the examination committee used a different format for the question," she said.

"They can either take a broad comprehensive view, or they can ask a more narrow question like they did last year."

Ms Taylor says the Board of Studies does not re-sit exams.

"The board does not re-sit tests, what we do is we take on board the difficulty of the examination through the marking process and through our standard setting process," she said.

But she acknowledges there have been complaints about the question.

"At the moment we've got about 20 complaints, that would be about 10 per cent of the number of schools that conduct studies of religion," she said.

"So we are aware that this is an issue, and we will just approach it as we usually do wih the best interests of the students at the centre of whatever we do."