Western governments and their allies are willing to begin lifting sanctions on Myanmar after victories by opposition leader Aung San Suu Kyi and her party in by-elections, but remain unsure about how quickly to reward the regime for signs of progress.

In the US, the Obama administration and some members of Congress want to begin dismantling sanctions but are constrained by the complex and overlapping laws imposed over the past 20 years. The European Union, Japan and Australia have signalled their inclination to begin reversing sanctions, raising fears that governments could end up competing to secure access for their companies to mining and infrastructure projects.

The weekend by-elections, in which Ms Suu Kyi’s National League for Democracy party won 40 of the 45 seats at stake, had been held up as a test of the regime’s commitment to the surprisingly rapid economic and political reforms of the past year.