Stable Noise-like pulse (NLP) operation is one of the attractive stable lasing state supported by a passively mode-locked fiber laser regardless of the total cavity dispersion. In this work, we have numerically analyzed the effect of cavity dispersion on supercontinuum generation by NLP. By using a highly nonlinear fiber of length 2 m, we demonstrate a broadened spectrum and emphasize the importance of the nature of dispersion regime in the spectral broadening. A quantitative comparison is also given with the supercontinuum generated by an ultrashort pulse of high peak power. © 2022 The Author(s)