By Neil Hughes

Published: 07:40 AM EST (04:40 AM PST)

Strong sales of the iPad are expected to have a "slight" negative impact on Mac sales, particularly on the low-end notebook models from Apple, supply chain sources have indicated.

Analyst Shaw Wu with Kaufman Bros. said in a note to investors Monday morning that checks with suppliers have revealed that the iPad availability is better than expected. This boost in supplies is said to be due to improved availability of screens.

However, he said overseas suppliers have also indicated that the iPad appears to be "slightly cannibalizing" low-end MacBook sales. Otherwise, Apple is poised for a strong quarter in Mac sales, with numbers indicating the company could sell a record 3.8 million in the September quarter.

Wu has adjusted his sales figures accordingly, and now expects iPad sales to blow past the Mac. He has forecast Apple to sell 5.7 million iPads in the September quarter, up from his previous prediction of 3.6 million. And he has also slightly reduced his expected Mac sales to 3.8 million, down from 3.9 million, due to the apparent cannibalization of low-end MacBooks.

Last week, Morgan Stanley said it believes the iPad has consumed as much as 25 percent of notebook PC sales since Apple's touchscreen tablet was introduced in April. Year-over-year sales of notebooks have seen a sharp decline in recent months.

But previous reports suggested that the iPad was not cannibalizing Apple's own Mac sales, as shipments continue to grow. And even with Wu's reduced prediction for September Mac sales, Apple is still on pace for a record quarter, even with supposed "cannibalization." This as notebook sales in the rest of the market have declined.

Wu also expects Apple to sell a record 11.5 million iPhones in the quarter, along with 9.5 million iPods. He also increased his gross margin prediction to 37.5 percent, up from 37.2 percent, due to favorable component costs.

Kaufman Bros. has increased its 12-month price target for AAPL stock to $374, up from $350.