People buy lotteries at a sports lottery shop in Baoji city, Shaanxi province, on Nov 21.[Photo/CFP]

An unclaimed lottery prize of more than 25 million yuan ($3.9 million) was put into the public Welfare Fund on Tuesday, marking the biggest lottery prize given up in China.

Two tickets sold at a lottery agency in Dongguan, southern China's Guangdong province, matched the seven numbers announced for the 15,132nd double chromosphere, a branch of China's Welfare Lottery, winning the special first prizes.

The local center of the Welfare Lottery has been looking for the winners, placing advertisements in media and banners near the agency, but without success.

According to regulations published in July 2009, if winners don't show up within 60 days after the draw the result will be void and the prize money will go to the Welfare Fund, a director at the Welfare Lottery center in Dongguan said.

The fund is used for public welfare, which is half used for local public welfare and half centrally, according to China's Ministry of Finance regulations.

In the past two months, some people called saying they were winners, but couldn't provide the lottery tickets.

Yuan Weiwen, the owner of the lottery agency where the tickets were bought, said a middle-aged couple was most likely the winners, telling when and how they came to the agency and bought tickets.

The man said he was a truck driver, and was delivering to a market across the road from the agency when he decided to buy tickets.

He said the numbers were randomly chosen by the computer, so he paid eight yuan for four lotteries in two separate tickets.