"We have issued a whip to our MLAs to support the AAP candidate," Delhi Congress President Arvinder Singh Lovely said.
Opposition Bharatiya Janata Party (BJP) fielded its candidate Jagdish Mukhi in the election scheduled later in the day.
Congress yesterday had backed the confidence motion by Chief Minister Arvind Kejriwal yesterday
Mukhi and Dhir are the only candidates left in the fray for the post after the deadline for filing nominations expired yesterday
AAP, which has 28 MLAs, needs the backing of eight Congress MLAs to secure the Speaker's post for itself. It can also count on the support of lone JD(U) MLA and an Independent who also backed the confidence motion.