And the manager expects to follow suit once the club have secured their Premier League status.
Gayle had been heavily linked with transfers to Swansea, Bristol City and Norwich during the past two transfer windows given his lack of first-team involvement.
Negotiations surrounding the forward's deal, which expires in 2017, had been ongoing since November but a two-year extension to that is to be signed.
It follows recent long-term commitments to the club by Scott Dann, Joel Ward, James McArthur, Jason Puncheon, Yannick Bolasie and Pape Souare.
"I believe (Gayle's) contract is agreed," said Pardew
"If it's signed, I'm not 100 per cent sure
"He's a player that scores goals and we've missed him for long periods this season."
Palace can reach the 40-point mark - typically considered enough to avoid relegation - with victory when they host Everton on Wednesday.
And Pardew said: "There's no way I'm going to sign a new contract if we're in danger of relegation, so I have to wait until mathematically we're safe and then hopefully sign a new contract here
"Of course I want to stay here
It was just a gentleman's agreement on my part."
Saturday's 1-0 defeat of Norwich earned Palace's first league victory since December 19 and lifted much of the pressure that had been building on them.
Pardew felt that run owed much to the absence through injury of significant players but Emmanuel Adebayor has returned to fitness and the expectation is that McArthur will be fit to face Manchester United next Wednesday, despite previous fears he could miss the remainder of the season.
"Adebayor is now fit, so he's gone into the squad (to face Everton)," said the 54-year-old.
"McArthur is very close, he is training with us now
We're hoping he could feature in the Manchester United game, which would be a huge bonus before the semi-final (of the FA Cup against Watford on April 24)
We've really missed him
"(Connor) Wickham was obviously involved (against Norwich) and he will be this game, whether he starts or not we'll have to wait and see."
Asked if victory over Everton would secure survival, Pardew said: "Yeah, pretty much
It would be very difficult for other teams to catch you at that level."
But he added: "Twelfth is a lot different to 16th, perception-wise, and we want to hunt down as many points as we can."
Source : PA
Source: PA