Prime Minister Narendra Modi will not be in the country on the dates of the conference.
The opposition Congress has invited 15 political parties from other countries and "all like-minded political parties" for an international conference in Delhi to commemorate the 125th birth anniversary of India's first Prime Minister Jawaharlal Nehru.
It has not, however, invited Prime Minister Narendra Modi, his party, the BJP, or any of its allies, said former minister and Congress leader Anand Sharma, while giving details about the two-day conference.
Among those on the invitation list is the Communist Party of China. Many world leaders had confirmed participation, said Mr Sharma.
Mr Sharma's invitation to other political parties in the country is being seen as the Congress' first attempt to reach out to regional players after its debacle in the national elections earlier this year.
The party posted its worst showing ever, winning only 44 seats in the Lok Sabha. Soon after, it has been completely marginalised in states like Haryana and Maharashtra that it ruled for multiple terms.
Prime Minister Modi will not be in the country on the dates of the conference. He is away on a 10-day tour of three nations beginning today.
Anand Sharma said the Congress conference would be chaired by party president Sonia Gandhi and vice president Rahul Gandhi would lead the party's delegation.
Mrs Gandhi and former Prime Minister Manmohan Singh were invited for Sunday's oath ceremony of 21 new ministers inducted into the Narendra Modi cabinet, but did not attend.
The government plans its own commemoration of Nehru's 125th birth anniversary and Mr Modi has reconstituted a committee set up for this by the previous Congress-led UPA government. The committee is now headed by PM Modi instead of his predecessor Manmohan Singh and includes Congress leaders like Ghulam Nabi Azad, Mallikarjun Kharge and Karan Singh.
On October 31 this year, the government organised a grand event to mark the birth anniversary of Sardar Vallabhai Patel, India's first home minister and PM Modi's hero. The Congress has sought to emphasise that Patel was a Congressman.