The Education Ministry has agreed to look into the allegations of political bias at the Qualifications Authority.
National claimed a question in last year's NCEA history exam branded its MPs as anti-Maori.
The exam asked students to answer a question as if it was 1980, and they were a National
MP "not sympathetic to Maori concerns".
Associate education spokesman Simon Power said the question was not an isolated incident as an NCEA economics exam question was also politically slanted, asking why free-market policies caused inequality.
Yesterday National added to their list of complaints about the NZQA, saying the authority had displayed a press release critical of the party education spokesman Bill English's stance on NCEA on the front page of its website.
The press release was removed after a complaint to the State Services Commissioner.
In Parliament, education and science select committee chairman Brian Donnelly asked Associate Education Minister David Benson-Pope to explain how the history question, which depicted a balding National MP, was not politicisation of exam process.
Mr Benson-Pope said exams were set under "considerable constraint" to ensure balance and he was confident proper process had been followed.
Mr Donnelly said the question would have been as valid if it had instead referred to just an MP.
Mr Benson-Pope conceded this was true, but said he was satisfied with NZQA's explanation.
The Associate Minister said he would be happy to look into the matters raised by Mr Power. On Tuesday Mr Benson-Pope asked NZQA for a report into the NCEA Scholarship awards after complaints from National education spokesman Bill English and some teachers that distribution of awards was unfair.
On Monday he said he would investigate the level of donations schools were requiring after a Herald survey found most state schools around Auckland were charging parents fees.
The cartoon: Who is it?
National leader Don Brash has said the cartoon, which featured in the NCEA exam, bears an unmistakable similarity to him, but he was not an MP in 1980 which the question refers to.
Other suggestions include New Zealand First MP Dail Jones, who was a National MP in 1980, and 1960s Labour leader Arnold Nordmeyer.
