Groups across the political spectrum still have to overcome many obstacles before they can join forces in future anti-Japanese campaigns, political commentator Johnny Lau Yui-siu warned yesterday.

At yesterday's City Forum, legislator Chan Yuen-han said last night's rally was the beginning of co-operation between groups with different political leanings.

'These kind of [anti-Japanese] activities are not election campaigns. We have to co-operate on the basis of our common goals and we should set aside our other differences,' she said.