R's boss Harry Redknapp recently suggested that the west London club and the Dutch giants were close to agreeing a fee for the 24-year old Iceland international but Sigthorsson's brother and agent has played down that speculation.
"The news about the ongoing negotiations is absolutely untrue," Andri Sigthorsson told Ajax Showtime.
"The last conversation we had with coach Harry Redknapp was five weeks ago. At the moment we are not talking, so I don't know where the news comes from."
Sigthorsson, who is valued at around £5million, joined Ajax from AZ Alkmaar in 2011 and has since scored 28 goals in 79 appearances for the Dutch Eredivisie champions. He has also netted 15 times in 23 internationals for Iceland.
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