"You have the Pakistan high commissioner calling separatist leaders for talks. Where has the diplomacy gone? Is this government going to endorse the behaviour of Pakistan?" Tewari told TimesNow news channel.
He said the government should explain the nature of the meeting between Basit and the separatist leaders on August 18-19.
Sujatha Singh will be in Pakistan on August 25 for talks with her counterpart Aizaz Ahmad.
Ahead of her visit, Hurriyat leaders Mirwaiz Umar Farooq and Syed Geelani have been invited by Basit for a meeting in New Delhi.
Former external affairs minister Salman Khurshid accused the government of double standards.
He said the decision to hold foreign secretary level talks was not in sync with the Bharatiya Janata Party's stated opposition to talks with Pakistan while the BJP was in the opposition.
"The BJP had been constantly saying that terror and talks cannot go hand in hand. Is that all forgotten," Khurshid asked.