China's top press watchdog on Thursday confirmed that the Zijin Mining Group, the country's biggest gold producer, tried to bribe reporters to hush up a major toxic waste leak at the company's copper mine in Fujian Province.

The General Administration of Press and Publication (GAPP), citing results of its probe, said reporters covering the scandal had refused to accept the money offered by the company and the local government.

The journalists continued to report the scandal, despite being offered large sums of money, the GAPP said.

Reporters from People's Daily, 21st Century Business Herald and Shanghai Securities News are among those who were investigated, it said, adding that the public is encouraged to tip off the administration if they know of any journalists who have accepted bribes.

Many reporters covering the July 3 toxic waste leak alleged that the Zijin Group tried to bribe them to cover up the matter, a charge the company denied.

Zijin Group came under fire after 9,100 cubic meters of wastewater from the Zijinshan Copper Mine spewed into the Tingjiang River from 4 pm on July 3 until 2:30 pm on July 4, killing thousands of fish. The company did not report the incident until July 12, nine days after the spill.

The toxic water later sailed downward and reached Guangdong Province, where the copper content of the river rose quickly and posed a big threat to the local fish farming industry.

Two weeks later, a second leak occurred at the same plant, though it was quickly capped to avoid further damage. About 500 cubic meters of waste was discharged.

The scandal caused a huge uproar within the country, as many believe the company had tried to shirk away from its responsibility by covering it up for as long as nine days while attributing the leakage to heavy rains.

Under mounting public pressure, the company later expressed "deep regret" for the incident and the "improper handling of information disclosure" in a statement on its website.

The scandal led to the dismissal of three government officials, including two local environmental protection officials. Qiu Heqing, the head of Shanghang county government, has also been suspended pending an investigation.

Chen Jiahong, vice-president of Zijin Mining Group, was detained over accusations that his company had caused serious environmental damage. Three executives of the copper mine were also placed under custody.

Local authorities asked the group to restrict its gold mining, cutting its production this year by 1 ton. Zijin produced 75.37 tons of gold in 2009.

Meanwhile, in a latest development, local authorities said all remaining toxic sewage at the Zijin Group's copper plant had been treated.

Repair work is also under way to step up measures to prevent such leakages at the plant, including the construction of a new and improved sewage pit that can better prevent wastewater from leaking into waterways.

The repair would take one year to complete, authorities said, adding that the plant will not be allowed to resume production this year.