The Magpies have found themselves in a worrying slump as injuries and suspensions have seen them left with a weakened side.
And with his side hovering just two points above the relegation zone with 16 games to play, Pardew has warned his players that Newcastle are not too good to go down.
"I think we shouldn’t be lost to the fact that we could be relegated," he told reporters.
"Better teams than the one I manage have gone down before. We definitely need a player or two in this window to make sure of our Premier League status. We’re under a little bit of pressure.
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"Our full accompaniment of players hasn’t been enough for a club of this size and we have been tested by injuries and suspensions, as well as the loss of Demba Ba.
"Some of the teams I’ve put out, in my opinion, haven’t been strong enough for Newcastle. We’re such a well-run club, financially. But we know that we’re going to need to invest in our team. We know that other clubs will."
Having missed out on striker Loic Remy to QPR earlier on the week, Pardew feels there is an urgent need to add to a squad widely perceived to be too weak.
"I don’t say think we have one of the weakest squads, but our squad is too weak," he added. "I’m being realistic.
"I’m not trying to say we’re a great team, that we’re going to cruise through the second half of the season because in my experience that won’t happen. We’re going to have to battle down there and it’s about time we realised we’re going to have to battle."
Remy joined QPR for a package worth twice as much as what Newcastle were prepared to offer, but Pardew believes this is the strongest they have been in the market for some time.
"I am as confident as I can be that we are the most aggressive [financially] we have been since I’ve been at the football club," he insisted.