The Citizens look to have learnt their lesson after losing former captain Robyn Johannes on a free transfer to Bidvest Wits, with Fielies having signed a new five-year deal.
The 26-year-old impressed alongside Johannes in the centre of City's defense last season, following his arrival from Milano United, and will now remain at the club until at least 2023.
Fielies, who made his Bafana Bafana debut at the COSAFA Cup in May, managed 31 starts for Benni McCarthy's side in 2017/18, missing just five matches for varying reasons including suspension.
He has already started all three of the Cape-based outfit's matches this season, parterning with Kouassi Kouadja in their opening 2-0 win over SuperSport United, before the arrival of former junior international Keanu Cupido.
City also have former Mamelodi Sundowns centre-back and national under-23 captain Kwanda Mngonyama on their books.