Sibal, however, added that Natwar's removal did not mean that he was guilty.
In the notice, Singh has raised strong objections on how the Pathak Committee report, submitted to the prime minister, was leaked to the media.
The PM asserted that no one who was guilty will go unpunished.
The two day meeting from May 31 will review the status of India's relations with these countries.
Jaitley warned that without filing an FIR, the Swiss court would not entertain any probe in the matter as in the case of Bofors.
Indian envoy arrives in New York to probe findings of Volcker panel
Jack Straw visits the Golden Temple and the Jallianwala Bagh in Amritsar.
The terms of reference were notified in the gazette through a resolution.
IT units in West Bengal have been promised protection during strikes.
Sehgal has denied links with Jagat Singh and the Congress party.
India had gone along with the United States and European Union in voting against Iran at the last IAEA meeting in Vienna in September, triggering strong protests by United Progressive Alliance's left allies.
Mukherjee will brief Natwar Singh on the situation in Nepal.
Volcker, former Chairman of the US Federal Reserve, is quoted as having admitted in a Los Angeles Times interview that he had agreed to change the language of his controversial report
He also said the G-4, comprising India, Germany, Japan and Brazil, should enter into renegotiation with the African Union
Volcker report: Natwar Singh rejects demand for resignation, claims PM's support
India, Russia for resolving Iran issue within IAEA framework
The party also announced countrywide protests to press the demand.
The IAF and USAF would begin a 12-day exercise at Kalaikunda base from November 7 and West Bengal's ruling CPI (M) has threatened to mobilise 30 lakh activists in statewide protests against the event.
"A lobbyist getting money from a foreign regime will seriously dent the national honour and prestige," Jaitley said.
He said while Indian participation in the Sakhalin-1 project demonstrated the joint capabilities and mutuality of interests, India was fully prepared with its technical and financial resources to expand its presence in the Russian energy sector.
Diplomatic sources also indicated that the Indian minister may brief the Russian leadership on the progress made in India-Pakistan composite dialogue.
This is part of high-level exchanges between India and Bhutan.
The Pakistan industry's contention was that by trading in dollars, there is a substantial economic loss due to conversion.
Also in the pipeline, are talks on more bus services.