The Indian envoy congratulated Imran Khan on his election victory, and gave a message of felicitation on behalf on Indian Prime Minister Narendra Modi.
The secrecy of ballot is guaranteed by the Constitution under Article 226 that states: "All elections under the Constitution, other than those of the Prime Minister and the Chief Minister, shall be by secret ballot".
Shortly after Modi's conversation with Khan on phone, speculations were rife that the latter would invite the Indian PM for his swearing-in.
India's comments followed remarks by Khan on 26 July in which he said he wanted to have good relations with India and work to resolve all outstanding issues through dialogue.
The relations between Pakistan and the U.S. nosedived this January after President Donald Trump accused Islamabad of giving nothing to Washington but "lies and deceit" and providing "safe haven" to terrorists.
Khan also expressed hope of Indian participation in the upcoming SAARC Summit, scheduled to be held in Islamabad soon.
The party will have to seek formal support from smaller parties or independents to have Khan elected prime minister.
Earlier, in his victory speech, Khan had also offered to build good ties with India. A senior leader of Pakistan Tareek-e-Insaf (PTI) told the reporters that Imran Khan has invited his Indian friends and former cricketer Kapil Dev, Navjot Singh Sidhu, Sunil Gavaskar to attend the oath ceremony.
According to the reply by Khan's counsel, photos of Khan's ballot were taken without his permission and the curtain, used around the ballot for secrecy, had fallen due to the crowd inside the polling booth.
Indo-Pak ties had been strained after the terror attacks by Pakistan-based groups in 2016 and India's surgical strikes inside Pakistan-occupied Kashmir.
Rouhani, for his part, said Tehran wished to further develop the bilateral relations with Islamabad.