According to the Daily Mail, Arsenal have asked Romero's representatives what a deal would look like, though Tottenham are unaware of their north London rivals' interest and would be unwilling to consider selling the 28-year-old to Arsenal at any price.
Atletico Madrid rekindled their own interest last month after Inter Milan made their move, with the Italian club having agreed a fee in the region of £34m with Spurs but yet to settle personal terms with the player.
Atletico are working through player sales before formalising a bid of their own, with the Spanish club in talks to sell left-back Matteo Ruggeri to Aston Villa for £19.7m, subject to the 24-year-old's approval, and closing in on a separate deal to send Nahuel Molina to Roma. The combined proceeds are expected to go towards a £30m offer for Romero, who is free to leave Spurs for the right price after the club strengthened its defensive options earlier in the window with the free signing of Marcos Senesi and the £52m capture of Jan Paul van Hecke from Brighton.
Arsenal, meanwhile, are exploring reinforcements at the back after William Saliba was ruled out for months with a back injury sustained at the World Cup, but the idea of signing Tottenham's club captain would be regarded as wholly unacceptable by Spurs supporters, and the club has given no indication it would entertain such a sale regardless of Arsenal's interest.
Romero has spent five years in north London since joining from Atalanta, playing a central role for Argentina in Lionel Scaloni's side that beat England in the World Cup semi-final before losing 1-0 to Spain in the final last month. He has come close to leaving Spurs before, notably following Ange Postecoglou's departure, and also suffered a knee injury during the club's dramatic fight against relegation towards the end of last season.
Reports elsewhere have suggested the fee under discussion between Tottenham and Inter runs closer to £38m-£40m rather than the lower figure previously reported, underlining how fluid the financial picture remains as multiple suitors continue to circle.
Romero was handed the Spurs captaincy last year and signed a contract extension running to 2029, only for the mood around his future to shift sharply following a difficult season under De Zerbi's predecessor and reported frustration over how his injury issues were managed.