In the paper, a minimal constraint based cuckoo search (CS) algorithm is proposed for solving transmission congestion problem by considering both increase and decrease in generation power. Thus, the proposed algorithm is used to optimise the real power changes of generator while transmission congestion occurred. Then, the power loss, generator sensitivity factor and congestion management cost of the system is evaluated by the proposed algorithm according to the transmission congestion. The proposed method is implemented in MATLAB working platform and their congestion management performance is analysed. The performance of the proposed method is compared with the other existing methods such as fuzzy adaptive bacterial foraging (FABF), simple bacterial foraging (SBF), particle swarm optimisation (PSO), and artificial neural network (ANN)-CS respectively. The congestion management cost is reduced up to 26.169%. Through the analysis of comparison, it is shown that the proposed technique is better and outperforms other existing techniques in terms of congestion management measures. Copyright © 2019 Inderscience Enterprises Ltd.