In metropolitan regions, emergency events request urgent response within a short time limit in order to minimise the damage and the number of fatality. Most of these events require different resources that are usually distributed over a large area. How to efficiently allocate the distributed resources to an event is a challenging research issue. Traditional centralised resource allocation approaches have difficulties to find out the best resource assignment within the event¿s time limits by considering the dynamics of the metropolitan environment and the event itself. In this paper, a multiagent-based decentralised resource allocation approach using domain transportation theory is proposed to handle an emergency event with multiple tasks. Experimental results indicates that the proposed approach can effectively generate the optimal resource allocation plans by considering multiple factors of an emergency event.