India opened e-visa applications for Canadian nationals on Wednesday, official sources said, two months after halting the service following a diplomatic spat over the killing of a Sikh separatist in Canada.

Official sources, who asked not be named, confirmed the development to AFP without giving details. The news was also widely reported by Indian media.

Relations between India and Canada have plunged since Prime Minister Justin Trudeau in September publicly linked Indian intelligence to the killing of Canadian citizen Hardeep Singh Nijjar, allegations New Delhi has called "absurd".

The Indian High Commission in Ottawa had in late October announced the resumption of visa services for Canadians but this did not include online applications.

The re-opening of e-visa services Wednesday came just hours before a virtual G20 meeting hosted by Indian Prime Minister Narendra Modi with Trudeau due to take part.

This would be the first time the leaders would meet, albeit online, since the row over Nijjar's killing.

Nijjar, who advocated for a separate Sikh state carved out of India, was wanted by Indian authorities for alleged terrorism and conspiracy to commit murder.

India has said it was willing to examine any evidence that Canadian authorities might present and temporarily stopped processing visa applications in Canada.

Canada announced last month it had withdrawn 41 diplomats from India as a result of the row.

Ottawa claimed that New Delhi was about to revoke diplomatic immunity for all but 21 of Canada's diplomats and their families, forcing it to pull out the others.

The Indian government had also advised its nationals not to travel to parts of Canada "given the increase in anti-Indian activities."

Tensions between Ottawa and New Delhi have created a delicate situation for close Canadian ally Washington, which is seeking closer ties with India in a bid to limit Chinese influence in the region.