The property developer behind plans for the world's tallest skyscraper, to be built in Changsha, Hunan province, said on Thursday that the project is still awaiting final approval from government authorities.

"So far, the project has already received some qualified assessment results, such as the construction plan and possible wind effects on the building," said Zhu Linfang, spokesman for Broad Group, the Changsha-based project developer.

Each step in the construction process must gain authorities' approval before it can be taken, she said.

The statement from Broad Group comes after a Xinhua News Agency report that said the company had not completed all the necessary application procedures before it started construction. The Xinhua report claimed the company was acting illegally.

The building, named Sky City, attracted media attention when its construction plan was published last year. If built, it will stand at more than 838 meters, higher than the 828-meter-tall Burj Khalifa in Dubai, currently the world's tallest building.

According to Broad Group's website, the tower in Changsha will have 4,450 apartments between the 16th and 170th floors and will include offices, a hotel, kindergarten, school, hospital, shops, gym and restaurants. The cost of construction is estimated at 9 billion yuan ($1.47 billion).

On Saturday, the company held a groundbreaking ceremony at the construction site in Wangcheng district, about 20 kilometers from downtown Changsha.

"It was only a ceremony. It does not mean the project is under construction," Zhu said.

So far, the company has been making preparations for work to begin, such as clearing rubbish from the construction site, but has not started building, she said.

The construction period is planned to run from October to April 2014, according to the company's website.

Xu Ning, an official in charge of urban-rural planning in Wangcheng district, declined to comment on the groundbreaking ceremony, but said, "The building is a key project for the city, and government authorities will release detailed information in the near future, after investigations."

Feng Yigang, head of Changsha's urban-rural planning bureau, said that the company has not yet received all the necessary approvals from government authorities. So far, his office had received no paperwork from Broad Group, he said.

On Thursday, about eight digging machines worked on the project's construction site.

"I began to work here this morning and my major task is to dig foundations for the building," said a worker who declined to give his name.

Wang Youwei, former vice-president of the China Academy of Building Research, said, "Some landmarks, including skyscrapers, are needed in China, especially in big cities, to show their economic achievement."

Chinese cities have a zest for skyscrapers. By the end of 2012, China had 10 of the world's 20 tallest skyscrapers, and more are planned, some aimed at grabbing the title of China's tallest.

Last year, soon after Wuhan said it would add 30 meters to a planned 606-meter building in order to make it the tallest, the developer of a skyscraper in Shenzhen announced that it would build a 660-meter tower. The record was soon trumped by another developer, which said it had started to select the location for a 700-meter skyscraper in Qingdao.

Wang said cities should be cautious in building skyscrapers, bearing in mind safety factors and energy consumption.