CPI will take a decision on the issue on Wednesday at a meeting of its Central Secretariat, D Raja, CPI National Secretary, said.
In a statement, the CPI(M) Polit Bureau said the party has decided to support the candidature of Ansari for the post.
Forward Bloc also extended its support to the UPA candidate for the August seven election.
"He was our candidate last time also. He never landed in a controversy in the past five years," Forward Bloc National Secretary G Deverajan told PTI.
RSP leader Abani Roy said his party will abstain in the Vice Presidential election. RSP has taken the same for the Presidential poll.
"Since we are opposed to the policies of UPA-II government, we are abstaining in the Presidential election. We will be taking the same stand for the Vice Presidential poll," Roy said.
CPI(M) has 27 MPs and Forward Bloc three lawmakers while CPI has six and RSP two.
The UPA is comfortably placed in the electoral college for the Vice Presidential poll comprising 790 MPs. With the backing of outside supporters like Samajwadi Party and Bahujan Samaj Party and others, the UPA has nearly 500 MPs on its side.
