In the early 1920s Southeast Asia, before communism compelled the creation of inter-colonial intelligence networks in the late period of the decade, a situation that can be called the ‘China problem’ emerged as an issue for the colonial powers in the region. This problem refers to the political activities by local Chinese populations in response to events that were taking place in China. The colonial powers, however, could not find a common solution to this issue, but instead dealt with it individually. An explanation to this lies in the fact that, unlike in Northeast Asia where the ‘Washington System’ shaped international politics in the 1920s, in Southeast Asia no such official framework had been established to deal with regional issues. This article sets out to demonstrate that under Britain's ‘informal empire’ in Southeast Asia, the colonial powers informally started to exchange information on domestic Chinese politics in their colonies as well as the political development in China. The ‘China problem’ was thus a catalyst that brought to the region ‘international’ politics and in particular the politics of immigration control.