Italian Football Federation president Carlo Tavecchio says an 18-team league would improve the quality of play in Serie A.
The league has struggled to keep pace with Europe's other top leagues and hasn't had one of its clubs win the Champions League since 2010, when Inter Milan lifted the trophy in Madrid.
Tavecchio, who has long been a proponent of a reduced field, was initially targeting a change for 2016, but has conceded it could take more time.
"It would bring an increase in the technical level of the teams and the fans who turn up," Tavecchio said of the benefits an 18-team league could bring.
"This week I will meet the leagues in order to give a 'gentle push' to the initiative, but it will not be easy.
"Clearly it cannot all be reduced in one year, but it needs a four or five-year plan."
Of his ideal league plan, Tavecchio added: "18 for Serie A, 20 in Serie B and two groups of 20 in the Lega Pro."
Meanwhile, Napoli president Aurelio De Laurentiis says he wouldn't mind a more drastic reduction in clubs, and wants to see a reformed Champions League in the future as well.
"I'm opposed to the reform of the Champions League as it has been designed," De Laurentiis said, as reported by Calcio e Finanza.
"Rather, we should make a League of 30 teams with the top-five Leagues in Europe. That would mean reducing the number of teams in the Italian League, but to be honest I think the Italian League should have no more than 10 teams.
"In Formula 1, the rest don't use cars from Formula 2 or Formula 3, so it's right that Serie A should only have teams which are financially stable, with good stadiums and with a sufficient number of fans."