Mending frayed diplomatic relations between India and Canada will be a long process after each side adopted maximalist positions, despite New Delhi's surprise move to ease some visa curbs on Canadians, officials and experts say.

India recently decided to partially restore visa services, weeks after suspending them in anger at Ottawa's claim that Indian agents may have been involved in the murder of a Canadian Sikh separatist leader from Punjab state.

Mutual recriminations since that accusation, which India strongly denies, have strained ties between the two countries — close for almost a century and with extensive links through the Sikh diaspora — to their worst in memory.