The Magpies have stepped up their interest in the England international in recent weeks, being prepared to spend a club-record fee.
However, Eddie Howe and club officials have been left frustrated in their attempts, recently failing with a bid in the region of £65m.
Despite Guehi having less than two years remaining on his contract, Palace chairman Steve Parish is seemingly prepared to hold firm unless Newcastle put together a more lucrative proposal.
Although priority is being placed on a new central defender, it remains to be seen whether Newcastle's hierarchy are prepared to go any higher.
Disasi emerges on Newcastle radar
According to David Ornstein of The Athletic, Newcastle are now assessing their options in the market as they attempt to make a statement signing at the back.
The report alleges that the North-East outfit have registered an interest in Axel Disasi, who is yet to play any football under new Chelsea head coach Enzo Maresca.
Disasi was absent throughout pre-season due to hernia surgery, and he was not deemed fit enough to feature in the squad for Sunday's Premier League opener versus Manchester City.
As it stands, the France international appears in line to represent Chelsea against Servette in the first leg of their Europa Conference League playoff on Thursday night having been selected in the squad.
Nevertheless, it remains to be seen how Chelsea's hierarchy would handle any interest in a player who they signed for £38.5m just over 12 months ago.
A further alternative...
Newcastle are also said to have held discussions with Bayer Leverkusen regarding a potential deal for Edmond Tapsoba.
The 25-year-old made a total of 46 appearances during the German side's history-making 2023-24 campaign, including 28 outings in the Bundesliga.
His status at Leverkusen has led to a wide array of major clubs being linked with the Burkina Faso international without tempting his club into a sale.
There are also still four years remaining on his contract, leaving a Newcastle side without European football on their calendar as outsiders to get a deal over the line.