Processor manufacturing problems threaten Apple's earnings, a leading analyst said last night.

Prudential Equity Group described Apple's much-publicised lack of availability of G5 processors from IBM as possibly "worse than anticipated", according to Forbes.

"Following a series of recent checks on Apple, we believe that availability of the company's 1.8GHz and 2.0GHz G5 processors may be worse than initially anticipated," it said.

Apple has said it "expects" shortages of these processors until July, but had been promised better supply in August. The analysts dispute this, saying: "IBM may be having difficulty meeting its revised supply commitments."

Supply problems could also undermine Apple's attempt at launching a G5 iMac, which the company recently delayed shipment of until September.

The analysts maintain a $27 target price on Apple's stock. Apple shares fell 6 cents (19 per cent) on this news, and news of a price war against its iTunes Music Store launched by Real Networks.