Shaw became the world's most expensive teenager earlier this summer when Southampton sold him for £30m, and Irvine is certain that the deal has made it difficult for the Baggies to approach full-backs in the current transfer window.
"When you look for full-backs now, the prices have changed as a result as what happened with Luke Shaw," the West Brom boss is quoted as saying by The Mirror. "Players are worth a lot more than before and that makes it more difficult for us.
"We need several more new faces in."
West Brom attempted to sign Aaron Cresswell from Ipswich Town last month before the defender joined West Ham United for a fee reported to be in the region of £7m.