In recent years, innovative composite sections have been gaining popularity owing to their reduced environmental impact and excellent mechanical properties at room temperature and in fire. Steel-reinforced concrete-filled steel tubular sections (SR-CFST) are one such typology in which an open steel profile is embedded within a CFST section. This type of section provides an enhanced mechanical capacity and fire performance when compared to regular CFST, and these benefits can be further improved with the use of high-strength materials [1]. In this work, a numerical model is developed to analyse the performance of slender SR-CFST columns under fire conditions. The model is first validated using data from the authors' own previous experiments [2] and the available literature. Then, an extensive parametric study is conducted to analyse the influence of several geometrical parameters – cross-sectional shape, outer tube dimensions, inner steel profile dimensions, section factor and slenderness – and the use of high-strength steel and concrete. Based on the parametric study results, a new simplified temperature distribution proposal, previously developed by the authors for SR-CFST sections [3], is revised to improve its accuracy. Additionally, the current design methods in the second generation version of EN1994-1-2 are assessed to verify their accuracy and applicability to SR-CFST sections in fire.