A man walks past the High Commission of Canada in New Delhi on Tuesday. AFP

India said on Tuesday it had expelled a Canadian diplomat with five days' notice to leave the country, just hours after Ottawa expelled the South Asian nation's top intelligence agent and accused it of a role in the murder of a Sikh separatist leader.

The development was the latest in an escalating row between the two nations, with Canada saying on Monday it was "actively pursuing credible allegations" linking Indian government agents to the murder in British Columbia in June.

The Canadian high commissioner, or ambassador, in New Delhi had been summoned and told of the expulsion decision, India's foreign ministry said in a statement.

"The decision reflects the government of India’s growing concern at the interference of Canadian diplomats in our internal matters and their involvement in anti-India activities," the ministry added.

Mourners carry the casket of Sikh community leader in Surrey, British Columbia, on Sunday. AP

"The concerned diplomat has been asked to leave India within the next five days."

Earlier on Tuesday, India dismissed the Canadian accusation as "absurd and motivated" and urged it instead to take legal action against anti-Indian elements operating from its soil.

Reuters