SYDNEY/SINGAPORE (Reuters) - Singapore Telecommunications (Singtel) shares fell more than 1% on Thursday in early trade after reports it was in advanced negotiations to sell a significant stake in Australian telco Optus to Canada's Brookfield Asset Management ( BAM ).

Those reports came after Singtel had dismissed an article in the Australian Financial Review (AFR) on Wednesday saying it would sell the entirety of Australia's second-largest telecommunications group for as much as A$18 billion ($11.93 billion).

Shares of Singtel were last down 0.8%, after sliding as much as 1.6% earlier in the session. The shares rose nearly 4% on Wednesday.

The telco did not respond to a Reuters' request for comment about a stake sale on Thursday. Brookfield declined to comment.

Singtel is in advanced talks over a "significant" stake sale to Brookfield, Reuters reported on Wednesday, citing a person with direct knowledge of the matter.

SingTel on Wednesday said Optus is an integral and strategic part of the group and it is committed to Australia for the long term.

In November, Optus drew public ire after a 12-hour network blackout that affected over 10 million Australians. The incident prompted an investigation, the departure of Optus' CEO and a A$1.5 million ($990,900) fine.

($1 = 1.5092 Australian dollars)