Merrill Lynch has warned that Apple's sales for the three months to December will fall short of expectations.

Steve Fortuna, Merrill Lynch analyst, said last week's launch of Apple's new iMac could have a detrimental effect on the company, negatively impacting the company's overall sales. Commenting on the new iMac Fortuna said its arrival, he said: "Rumour mongering preceding the iMac's launch will have prompted Apple customers to defer their purchases until after the new year."

Apple has forecast $1.4 billion sales for its first fiscal quarter, however Fortuna said that $1.4 billion revenues is actually the best Apple can expect.

Fortuna also said there is a 10 to 15 per cent "downside risk" for Apple's shares.

Apple shares closed at $21.05 last Friday down $1.85 from last Monday's close of $22.90.