Sources with knowledge of the matter told Reuters on Tuesday that China was considering a merger between the two major metals and mining firms as Beijing pushed to consolidate its bloated state-run enterprises to help increase efficiency and competitiveness.

"After checking with the company's owner China Minmetals Group, the group said it was not aware of a merger deal and had not been notified by relevant authorities on the matter," the listed units said in similar statements.

The China Minmetals' subsidiaries that issued statements include China Minmetals Rare Earth Co Ltd (>> China Minmetals Rare Earth Co Ltd), China Tungsten And Hightech Materials Co Ltd (>> China Tungsten and Hightech Mtrls Co Ltd), Minmetals Development Co Ltd (>> Minmetals Development Co., Ltd.), Minmetals Capital Co Ltd (>> Minmetals Capital Co Ltd) and Zhuzhou Smelter Group Co Ltd (>> Zhuzhou Smelter Group Co.,Ltd.).

On Wednesday, the five listed companies' shares ended up between 4.6 percent and 10 percent.

China National Gold's unit Zhongjin Gold Corp Ltd (>> Zhongjin Gold Co., Ltd), whose stock rose 6 percent, also issued similar comments.

(Reporting by Lee Chyen Yee in Singapore and Meg Shen in Hong Kong; Editing by Adrian Croft)