Alam, a third term MLA, said this was needed to strengthen secular forces. There are four Congress members in the present 243-member Bihar Assembly.
Alam said he had made his point before senior party leaders. Chief minister Nitish Kumar had flown to Kisanganj to attend Alam's marriage function in April.
Congress Legislature Party leader Sadanand Singh, however, said this was Alam's personal view.
"Any decision on whether to go for tie with JD(U) or not will be taken by the party high command," he said and drew attention towards the statement of AICC Vice-President Rahul Gandhi that such decisions are taken by senior party leaders.
In the event of separation, Nitish Kumar whose party has 118 members in the Vidhan Sabha, including Speaker Udai Narayan Chaudhary, would require support of four MLAs to achieve the magic figure. Five of the six Independents have vouched support to JD(U).