The goalkeeper can play into his 40s according to his representative, who also insists the Azzurri are one of the top-five teams in the world after their Confederations Cup display
The 35-year-old came in for criticism during Italy's Confederations Cup campaign and was even labelled a "pensioner" by Franz Beckenbauer after the Bianconeri's 2-0 loss to Bayern Munich at the Allianz Arena.
However, Martina is certain his client will ease towards 40 and possibly even appear for the country during the World Cup 2018 in Russia.
"Gigi can reach 40 quietly and without a fuss," the player's representative told Radio Sportiva.
"He can even make it to the World Cup in 2018. Gigi is an absolute champion and still the strongest goalkeeper of them all.
"The penalty shoot-out against Spain was unlucky, those were simply unstoppable. A goalkeeper can't really be judged by a shoot-out."
Martina also feels Italy are back at the highest level following their third-placed finish at the Confederations Cup and can be considered one of the favourites to win the World Cup in Brazil next year.
"The Confederations Cup was an event which prepared the team well for next year," he added.
"Italian football has got back to its optimum level, we are back among the top five in the world."