Tharoor also said he felt a "bit rich" to be criticised by the BJP and claimed that Swaraj had mentioned Prime Minister Narendra Modi 10 times in her speech and spoke about India only five times.
Questioning whether Swaraj's address was a UN speech or BJP slogans, he said she devoted the first half of her speech mentioning Modi's vision for a "New India" and discussing programmes as the Swachh Bharat Mission.
"Bit rich to be criticised by the BJP for describing Sushma Swaraj's speech as a campaign speech. She mentioned Narendra Modi 10 times during her address and spoke about/on behalf of India only five times. If you use the UN as a political platform you can't hide behind the flag," Tharoor said on Twitter.
"Most of the first half of the Sushma Swaraj speech was devoted to plugging Narendra Modi's vision for "New India": Swachh Bharat, Swasth Bharat, Samarth Bharat, Surakshit Bharat, Shikshit Bharat, Viksit Bharat, Urjawan Bharat, Shaktiman Bharat. Was this a UN speech or BJP slogans?" he asked.
The BJP Monday strongly reacted to Tharoor's reported criticism of External Affairs Minister Sushma Swaraj's UN speech and had said that the opposition party defied a convention of all political parties speaking in the same voice on India's stand abroad.
BJP spokesperson Sudhanshu Trivedi had said the Congress is being increasingly seen to be standing with Pakistan as Tharoor's statement was not an isolated incident and the opposition party often spoke the language of the neighouring country.
He had told a press conference that the Congress should apologise to the country and said its stand on various issues appeared similar to that of Pakistan in "intent, language and style".
On Sunday, Tharoor had reportedly said in Kerala that Swaraj's speech was aimed at her party's voters on the subject of Pakistan rather than constructing a positive image of India in the world.
Trivedi had said, "There has been an established convention in politics since independence that political parties are unanimous on foreign issues, at least when it comes to taking a stand at the United Nations (UN) where India's position is not of a political party."
"Pakistan has always opposed us there. For the first time a senior Congress leader is also criticising," he had said, adding Tharoor had earlier used the term "Hindu Pakistan" to attack the BJP's rule.
The BJP leader had also cited comments of Congress leaders like Mani Shankar Aiyar and Ghulam Nabi Azad to liken it with Pakistan in its opposition to the Modi government.
He had said the Congress has lost the "moral right" to claim to be the party of Mahatma Gandhi, wondering if the Congress in zeal to oppose Prime Minister Narendra Modi was also opposing the country.