China said Thursday that last year's massive Sichuan earthquake left 5,335 schoolchildren dead or missing, releasing its first official tally just days before the anniversary of the disaster.

The number of children killed in the May 12 quake is highly sensitive as many bereaved parents say school buildings were shoddily constructed and collapsed too easily when the quake struck, while structures nearby stood firm.

Some parents staged protests in the days following the 8.0-magnitude quake -- which left nearly 87,000 people dead or missing -- alleging that corruption resulted in school walls that were like "tofu".

State media had said previously that 14,000 schools suffered damage in the quake -- half of which collapsed entirely -- while early estimates of the numbers of students and teachers killed were put as high as 9,000.

Tu Wentao, head of southwestern Sichuan province's education department, attributed the year-long wait for the exact student death toll to the need to compile figures from various government agencies.

"These numbers were reached through legal methods. We have wide agreement on these numbers," Tu told a press conference in the provincial capital Chengdu, speaking as part of government efforts to mark Tuesday's anniversary.

The quake also left another 546 students disabled, according to the data, which did not include any deaths in surrounding provinces.

Yu Jie, head of the Sichuan reform and development commission, said the government was taking the issue of the collapsed buildings seriously.

"I can tell you this -- if some shoddy construction problems exist and have brought disaster to the people, we will resolutely investigate and severely punish this," he told reporters.

According to government figures, 3,340 schools need to be rebuilt.

Rights groups have heavily criticised Beijing for not being upfront about the schools issue. Officials have sealed off school ruins, barred media coverage of the subject and jailed activists investigating the issue.

On Thursday, a Sichuan official accused Western reporters of stirring up trouble.

"A very few journalists are not going to the disaster area to report, but are inciting the crowds, asking people to organise," Hou Xiongfei, vice head of the provincial propaganda department, told reporters in Chengdu.

"We do not welcome these kinds of people and... will handle them in accordance with the law," he added, without giving specific examples.

The Foreign Correspondents Club of China on Wednesday urged reporters to be cautious in quake-hit areas, saying it received three reports of foreign journalists being shoved, punched or otherwise harassed.

"Given the violence of the encounters and an apparent increasing frequency of reports, it seems the situation is becoming more volatile and we advise extra caution when visiting these areas," it said in a statement.

China has required foreign journalists to register with local authorities if they want to report on the anniversary of the quake.

Human Rights Watch released a statement Wednesday calling for China to open up about the quake, compensate victim's relatives, and allow parents to sue.

"Parents of student quake victims, who are trying to understand how and why their children died, deserve answers and compassion, not threats and abuse," Sophie Richardson, the group's Asia advocacy director, said in the statement.

The quake injured 375,000 and left more than five million homeless, according to previous official estimates. Sichuan officials also said Thursday 630 children were orphaned.