Sri Lankan Foreign Minister G.L. Peiris is arriving here Sunday to invite Prime Minister Manmohan Singh for the Commonwealth Heads of Government Meeting (CHOGM) in Colombo in November.
Peiris, who arrives Sunday evening, will meet Manmohan Singh on Monday to hand over the invitation for the Nov 15-17 event. He will also meet External Affairs Minister Salman Khurshid.
Both sides would also discuss matters of bilateral interest, including the issue of the 13th Amendment of the Sri Lankan constitution, carried out with Indian backing in 1987 to ensure autonomy to provinces and by extension to the Tamils in the island's north and east.
President Mahinda Rajapaksa's government has threatened to dilute its provisions, causing dismay in India.
Sri Lanka's Leader of the Opposition Ranil Wickremesinghe is also to visit New Delhi next week to hold talks with Indian leaders.
Wickremesinghe, who would be on a private visit to India Aug 21-22, has requested a meeting with Indian leaders, news reports said.
In Chennai, DMK president M. Karunanidhi Saturday warned of rail blockades and black flags on houses and commercial establishments across Tamil Nadu if Prime Minister Manmohan Singh did not declare that India would not participate in the CHOGM in Colombo.
In a statement, Karunanidhi said: "The prime minister without neglecting Tamils' demand should categorically and openly declare that India will not participate in the meet."
He said the Sri Lankan government has lost credibility in the international forum and it is trying to dilute the provisions of 13th amendment to its constitution.
The DMK had walked out of the United Progressive Alliance (UPA) coalition over the Sri Lankan Tamils issue in March.