Network-on-Chip (NoC) has been proposed to replace traditional bus based architectures to address the global communication challenges in nanoscale technologies. In future SoC architectures, minimizing power consumption will continue to be an important design goal. In this paper, we present a novel heuristic technique consisting of system-level physical design, and interconnection network generation that generates custom low power NoC architectures for application specific SoC. We demonstrate the quality of the solutions produced by our technique by experimentation with many benchmarks. Our technique has a low computational complexity, and consumes only 1.25 times the power consumption, and 0.85 times the number of router resources compared to an optimal MILP based technique  whose computational complexity is not bounded.