Wasnik is the Congress general secretary in-charge of Kerala.
The high command's decision came as the image of the Congress-led UDF government has been severely hit following the allegation of involvement of some members of Chandy's personal staff in the solar panel scam.
Wasnik, who will visit the state on June 24, will convene a meeting of the party's state executive and parliamentary party on June 25, party sources said.
He will also hold discussions with leaders of the Congress allies in the state, they said.
State Congress chief Ramesh Chennithala and newly appointed AICC secretarty V D Satheesan met party president Sonia Gandhi separately and are learnt to have apprised her of the situation in the state.
Both the leaders have also held discussions with Gandhi's political secretary Ahmed Patel, Defence Minister A K Antony and Wasnik.
Asked about the developments, Chennithala sought to defend the beleaguered chief minister, saying Chandy has already taken action against the staff by removing them from his office.
Chandy had removed a personal assistant and a gun man from the Chief Minster's Office a week back after they were found to have engaged in frequent telephonic conversations with Saritha Nair, an accused in the solar panel scam.
The Opposition LDF has unleashed a strong campaign within and outside the state assembly demanding Chandy's resignation.
The solar panel scam pertained to financially cheating a large number of people by fraudsters Saritha Nair and Biju Radhakrishnan by offering them solar energy solutions. The duo has been arrested and remanded in police custody.