In a statement carried on the Straits Times website, Ng said his five-man consortium had become "increasingly frustrated with the process of dealing with the club administrators".
However, the report added that he could relaunch his bid if administrators Duff and Phelps failed to reach a deal with other potential bidders.
Sources close to the talks in Britain confirmed that Ng had pulled out. He is chairman of Hougang United, a professional team in Singapore's small S-League.
Rangers, Scottish champions a record 54 times, went into administration in February over unpaid tax bills. They suffered a 10-point penalty and have recently lost their league title to Glasgow rivals Celtic.
Ng's group emerged as a front-runner this week when the administrators said the Blue Knights consortium led by former Rangers director Paul Murray were withdrawing from the bidding.
However, reports have said the Blue Knights would be ready to revive their interest.
Brian Kennedy, a Scottish businessman who owns English rugby club Sale Sharks, has made a verbal offer and a U.S. consortium is also still in contention.
There are a number of issues complicating efforts to rescue Rangers. The club owes around nine million pounds in unpaid taxes and faces a much larger potential liability in another tax dispute dating back over a decade.
Craig Whyte, who bought an 85 percent stake in the club a year ago for a nominal one pound, also raised more than 20 million pounds against future season ticket sales in a deal with a company called Ticketus.
The Scottish Premier League is also meeting at the end of the month to decide if clubs which go insolvent and are then reformed should be docked points in future seasons.
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