Nicola Sturgeon has hit back at claims that Scotland's exam system is in chaos as Labour highlighted a drop in the number of pupils gaining qualifications in languages.

Kezia Dugdale, Scottish Labour's deputy leader, said the number of students passing the new National exam - which replaced standard grades - in French and German had dropped by more than 40%.

Ms Dugdale, who last week raised concerns about the Higher maths exam, called on the First Minister to "take her head out of the sand and clean up this mess".

She told Ms Sturgeon that expert Dr James Scott had already raised fears about "some modern languages disappearing from our schools altogether", with fewer pupils studying languages.

Ms Dugdale said: "Teachers and head teachers have warned ministers of chaos with the new exams, I have repeatedly raised problems with the new exams. Thousands of pupils have signed a petition telling ministers there is a problem with the new exams."

The MSP raised the issue at First Minister's Questions in Holyrood as the EIS teaching union gathered in Perth for its annual general meeting, with Ms Dugdale saying they were "deciding whether to boycott the new exams altogether".

Ms Sturgeon told her: "I assume that wasn't Kezia Dugdale endorsing a boycott of the new exams. I certainly hope she will clarify that matter."

The SNP leader said: "There has been an issue raised, Kezia Dugdale raised it last week, an issue of concern with the Higher maths exam, the feeling on the part of many students that that exam was too difficult in terms of how they had been taught.

"I gave a lengthy and detailed explanation last week of how the Scottish Qualifications Authority deal with those situations to make sure no young person is disadvantaged because of that.

"But to make a leap from that, as Kezia Dugdale has just done, to describe the new exam system as being in chaos, I think is deeply, deeply irresponsible and does a great disservice to young people and teachers across our country who are working so hard for those exams."

She said she would "study carefully" the statistics the Labour MSP had highlighted but added that Ms Dugdale had previously made an error when raising figures on exams.

During exchanges in Holyrood, Ms Dugdale referred to research by Dr Scott, from the University of Dundee, saying this showed a fall in the number of S4 pupils taking and passing exams in French, German, Chinese and Gaelic.

The Labour deputy leader said: "Dr Scott's published research shows that in the first year of the new National exams the number of people sitting French and German fell by 37%. The numbers passing fell by more than 40% - almost half.

"That is appalling - a 40% drop in S4 pupils getting a qualification in one of the key European languages."

She added that while the Scottish Government had set the target in 2012 of doubling the number of students passing exams in Chinese, the research showed candidates fell by more than third last year and the number of passes was down by 42%.

"We know the SNP Government is failing when it comes to European languages, we know Scotland is going backwards when it comes to Chinese."

She also said that in the first year of the new National exams, Gaelic learners fell by 21% and the number of pupils who passed the subject fell by more than a quarter.

Ms Dugdale added: "Dr Scott's analysis describes the decline in Gaelic under the SNP as significant given all the money that has been invested in this area."

Ms Sturgeon told MSPs: "I will look very carefully at the research Kezia Dugdale has cited today, I'll do that for two reasons.

"Firstly it's important I do that because it's important we look carefully and follow the lessons of any research that is published.

"But the second reason I will do that is the last time Kezia Dugdale quoted research to me at First Minister's Questions about exam passes she mixed up, I assume inadvertently, entries for exams and the number of candidates sitting exams."

Ms Dugdale insisted it was "not the case" that she had misrepresented the work of Dr Scott.

She told the SNP leader: "I spoke to Dr James Scott this morning and the numbers I am using today are accurate and are in his published paper, which is actually funded by the Scottish Government."

But Ms Sturgeon stated: "The last time Kezia Dugdale cited the research of Dr Jim Scott, she said that research showed the number of candidates gaining level 5 qualifications was down by almost 102,000.

"Actually, at all levels there are only about 150,000 candidates in every year.

"She confused the number of candidates with the number of entries, because candidates of course are presented for multiple exams. That is the reason why I have a degree of scepticism."

She told the Scottish Labour deputy leader: "I will study carefully the figures she cited, I will be particularly looking to see that she hasn't made the same mix-up she did last time between candidates and numbers of entries."

She also stressed: "As First Minister, as leader of this government, we will continue to focus on making sure that we have an education system that is providing the education, the skills and the training that our young people need. We will not be diverted from that objective, that is our responsibility."