China's much-anticipated high-speed rail link between Beijing and Shanghai will go into service on July 1, state media said Thursday, after a corruption scandal that toppled the former railways minister.

A ceremony will be held on June 30 to mark the opening of the link, before trains go into commercial use on July 1, the Xinhua news agency reported, citing the railways ministry.

The ministry declined to confirm the start date when contacted by AFP.

The $33 billion link, which has been operating on a trial basis since mid-May, will cut the journey between the two cities to four hours and 45 minutes -- two hours less than the fastest current trip by train.

The Beijing-Shanghai flight takes about two hours. But travel to the airports is in itself time-consuming, and the busy air route is often subject to delays and cancellations, making train travel an attractive option.

One-way ticket prices will range between 410 yuan and 1750 yuan ($63 and $270) subject to further adjustments, vice rail minister Hu Yadong said last week, compared to about 1,300 yuan for a flight between the two cities.

Work on the high-speed railway started in April 2008 with a planned investment of 220.9 billion yuan.

China has invested heavily in its high-speed rail network, which reached 8,358 kilometres (5,180 miles) at the end of 2010 and is expected to exceed 13,000 kilometres by 2012 and 16,000 kilometres by 2020.

But huge investment has also made the sector a hotbed for corruption, which has raised concerns over the costs and safety of the high-speed rail links.

China's state auditor in March revealed that construction companies and individuals had last year siphoned off 187 million yuan ($28.9 million) in funds meant for the Beijing-Shanghai link.

This followed the sacking of former railways minister Liu Zhijun in February, who had allegedly taken more than 800 million yuan in kickbacks on contracts linked to China's high-speed rail network.

The railway ministry has said the trains would run between 250 and 300 kilometres (155 and 188 miles) per hour on the Beijing-Shanghai link, although the line is designed for a maximum speed of 380 kph.

The speed is in line with a nationwide directive made public in April that said all high-speed trains must run at a slower pace than previously announced -- no faster than 300 kph -- to make journeys safer.

The speed of trains on the fast rail linking Wuhan in central China and Guangzhou in the south would also be lowered to 250 and 300 kilometres per hour from the beginning of next month from the current 350 kph.

Zhou Yimin, a former deputy chief engineer of the railway ministry, said Liu's claims that China's high-speed trains could run at 350 kph or even 380 kph was "fraudulent" and totally ignored safety, Chinese media said this week.

China has not acquired core technologies of high-speed trains and all the key parts of its trains running at speed above 200 kph are bought from foreign companies like Siemens, he said, according to the reports.