The Congress on Friday issued a show cause notice to Rae Bareli MLA Aditi Singh for defying whip and attending the 36-hour special session of the Uttar Pradesh Legislative Assembly.
It has asked her to submit the reply within two days.
"The party had decided to boycott the two day session of the house and had also issued a whip to ensure that no MLA attends it. You were also informed about it individually but you defied the party instructions," Congress Legislature Party leader Ajay Kumar Lallu said in the notice.
"Your defied party whip and took part in the proceedings. This amounts to indiscipline and anti-party activity," he said, asking her to submit the reply in two days or else action will be taken against her.
Singh, who had remained absent from Congress's Gandhi Jayanti functions led by party general secretary Priyanka Gandhi on October 2, surprised all by attending the proceedings of the house the same evening "rising above party lines".