According to a report from the Times, Saints are chasing the promising young forward, who appears to be set to leave City in the near future.
Duncan, the cousin of ex-England international Steven Gerrard, is attracting a lot of interest from clubs in the top flight, as his contractual situation remains unclear at the Etihad Stadium.
The 16-year-old was in action for the England Under-17s in midweek, and helped them to come from 2-0 down to win 3-2 against their Portuguese counterparts.
If Duncan is to be snapped up before signing a new, professional deal at the club, it’s reported that City will be entitled to compensation.
However, the league leaders hold Duncan in high regard and don’t want to lose him at such a young age.