Moreno, now 23, signed for City in 2016 for an initial £4.75m from Atletico Nacional after helping them to the Colombian league title with five goals in 27 games, earning a national team call-up and impressing in the Copa Libertadores.
And Coritiba Director of Football Paulo Pelaipe told Banda B radio: "We didn't give up. We have the international transfer window, which starts in October, and let's see if we can do it, because we believe it would help us a lot here in Coritiba."
Pelaipe added Moreno has a high salary which will require "very big financial engineering" to complete the move. He also said Coritiba are not clear on what City's plans are for the player.