The Reds are chasing Southampton defender Virgil van Dijk while La Liga giants Barca want Philippe Coutinho before Thursday’s deadline.
Cameron feels the fact Liverpool will now compete with the elite Spanish sides in the Champions League is making things tougher for them.
He said on BBC Radio 5 Live: “It's always tough to get big players in because they're fighting with the likes of Real Madrid and Barcelona. You have to go to the lower half of those.
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“You have a guy who has proven himself at Southampton and he's done very well over the last couple of years.
“It would be a big loss to Southampton but a massive boost for Liverpool.”
Cameron also opened up on Coutinho potentially leaving Anfield for the Nou Camp.
He explained: “If I'm Coutinho, you want to go, it's an opportunity you can't turn down?
“How often do Barcelona come knocking and say we want you to come in here and replace someone of the likes of Neymar.
“If he doesn't go, it's going to be hard mentally to deal with that knowing the club turned you down a little bit.
“If you're going to play alongside Messi, you're only going to improve your game.
“Playing against him, he's quick, sharp, he takes on guys in any way. Give him some space and the ball is in the back of the net.
“He did it to us at home last season and he had one opportunity.
“He came on as a sub, tied the game for them and all because he had one chance.”
Liverpool were in stunning form yesterday, thrashing Arsenal 4-0 at Anfield.
