The 22-year-old defender has an £8 million relegation release clause in his contract and is reported to be keen on a move back to the Premier League as soon as possible, rather than featuring in the Championship next season.
Cardiff are thought to be willing to sell their star man in a bid to balance the books for the upcoming campaign.
Alan Pardew is desperate to add depth to his Newcastle squad and is also thought to have a particular interest in bringing in more British faces at St James' Park.
Newcastle are renowned for their heavy French contingency, but following the signing of Jack Colback earlier this month (the Magpies' first British signing in almost three years) it appears that Pardew's preferred transfer policy of mainly shopping abroad is beginning to waver.
Caulker enjoyed a solid season at Cardiff last term and although the side eventually went on to be relegated at the foot of the table, the 22-year-old defender was one of the few shining lights in the squad.
There is no doubt that Caulker would be interested in a move to Newcastle, with the defender not only likely to see it as a step up but also a good opportunity to re-ignite his so far short England career.
Caulker received his only full England cap whilst on loan at Swansea City from Tottenham Hotspur in 2012. The 6"3 defender started in a friendly against Sweden and went on to net a debut goal as he turned in a free-kick from Steven Gerrard inside the six-yard box.
With Mapou Yanga-Mbiwa expected to leave Newcastle United in the coming weeks, a deal for Caulker could be on the cards, but Newcastle may be put off by a fee as high as £8m and this could prove a stumbling block in any possible deal to bring the 22-year-old to St James' Park.