Irvine left his post to as number two to former Lilywhites boss David Moyes at Everton earlier in the week to take the reins at Deepdale.
And Shaw has suggested there will be funds available for Irvine to invest as he looks to pull the club away from the lower reaches of the Championship table.
"We've always attempted to support our managers and it's probably inevitable that Alan will want to strengthen," Shaw told the Lancashire Evening Post.
"We'll give Alan the best possible assistance and all the help we can give him if he decides he needs to bring fresh faces in.
"Alan will be having a look at things over the next few days and weeks and he'll reach his own conclusions on the squad.
"If there's business to be done, we'll do our best to carry it through."