The Daily Mail reports that the Magpies are preparing to offer a £8 million bid for the Norwegian defender. Celtic are understood to want much more for the 22-year-old, but will struggle with their bargaining power as Ajer enters the last year of his deal this summer.
Ajer’s national team boss Stale Solbakken recently called for the player to leave Scottish football in the next transfer window and find a new challenge elsewhere.
Meanwhile, there is interest from the English Premier League in Rangers centre-back Filip Helander, according to reports in his homeland.
The Swedish star is on the radar of Aston Villa and ex-Celtic manager Brendan Rodgers, who is in charge of Champions League hopefuls Leicester City.
He could even be replaced by a defender in Sweden’s top flight as Elfsborg's Joseph Okumu is reportedly a target for Steven Gerrard’s men.