The 29-year-old has struck three times in five Premier League outings since joining the Saints after a goal-laden spell with Feyenoord.
"On top of scoring 50 goals in 57 games in Holland, Pelle is now also scoring in England," Conte told Corriere dello Sport.
"We are watching him, as we are with others. I want a squad of 25-30 players based on meritocracy.
"I am not interested if your name is x or y, as I want 30 people who think 'we are the Nazionale'. If a player is talented, you play him."
Pelle represented Italy's Olympic football team in 2008.