Pardew this week revealed he wants to make up to four major signings as he prepares for the new campaign having lost star man Yohan Cabaye to Paris St Germain last month.
The £19million-plus the Magpies banked for the France international remains untouched after since-departed director of football Joe Kinnear failed to find a replacement before the transfer deadline.
However, Lee believes it could take far more than that for Pardew to rebuild a squad which may yet be further depleted during the closed-season.
Asked if four big signings would be enough, the 48-year-old former midfielder, an ambassador for the Budweiser Open Trials campaign, which will provide amateur footballers with the opportunity to play at Wembley in front of professional scouts, told Press Association Sport: "It's a start. Is it enough? No, probably not.
"Is [Loic] Remy going to sign for us? I am sure after the season he has had - he's only on loan - he will have a lot of options and if he sees Newcastle selling Cabaye, their best player, what's he going to think?
"It's not as though he's going to have a shortage of offers, so my instinct would say he won't sign, so you have got to replace him; there are rumours that [Papiss] Cisse is not happy and is going to go; Shola Ameobi is out of contract; [Cheick] Tiote, is he going to be happy with Cabaye going? I think there will be a lot of people after him.
"You have to keep these people happy - [Fabricio] Coloccini again, is he going to stay? There were rumours he wanted to go back anyway.
"Again, it comes down to when you start selling players, your best players that are left are not going to be happy."
Lee was not surprised to see Cabaye leave the club after he was unsettled by Arsenal's bid in August, but was astonished that a replacement had not been lined up before PSG were given the green light.
He said: "Everybody knew it was coming. That's fine, but you have to have somebody lined up to replace him. He's your best player.
"He went very, very cheaply as well - if you look at [Juan] Mata going for £37million, he's a bargain, he's an absolute bargain for PSG.
"We had to have someone lined up to replace him straight away, but typical Newcastle, we didn't."
Whatever happens during the summer, Pardew faces the task of trying to plug the gap left by Cabaye.
His initial attempt to do that in last weekend's Tyne-Wear derby proved less than effective as Newcastle were trounced 3-0 by Sunderland to invite further recriminations after a dreadful week or so for the club, and Lee admits the manager has a problem on his hands.
He said: "You look around and you think is there anybody there who can actually do that at the moment? I would say no.
"It's a major rebuild for Newcastle in the summer, but it depends how much money you are given. For a major rebuild, you need to spend a lot of money. Will Mike Ashley give him that money to do that?"