The High-Energy Factorisation (HEF) coefficient function or impact factor for the hadroproduction of the state ${}^1S_0^{[1]}$ of a heavy quark-antiquark pair ($Q\bar{Q}$) at forward rapidities is computed at NLO in $\alpha_s$. This impact factor is an integral part of the resummation procedure for higher-order QCD corrections to the hadroproduction cross sections of $\eta_c$ or $\eta_b$ mesons at forward rapidities in collinear factorisation (CF), enhanced by logarithms of partonic center of mass energy. The NLO computation results of which are presented in this contribution, is an important step towards an extension of aforementioned resummation beyond the Leading Logarithmic Approximation(LLA).