March 13 (Reuters) - Singapore Telecommunications

is in advanced talks with Canadian private equity

Brookfield to sell a significant stake in its

Australian telecom unit Optus, a source with direct knowledge of

the matter told Reuters on Wednesday.

SingTel in an exchange filing earlier denied a media report,

which stated the telecom firm was in talks with Brookfield to

sell Optus in deal which could value the Australian firm for up

to A$18 billion ($11.90 billion).

($1 = 1.5131 Australian dollars)