Sources said that both Rahul and Sonia will address the rally, whose timing will be finalised after the rally of Prime Minister Narendra Modi.
Reports had it that Modi is likely to address a rally in the national capital on January 10 to bolster his party's campaign.
Polls in Delhi may take place in February and neither Congress nor BJP has declared their chief ministerial candidates so far.
In the last Assembly elections, Congress had fielded its three-time Chief Minister Sheila Dikshit and the BJP had declared Harshvardan as its candidate.
The Assembly polls in December 2013 had thrown up a fractured mandate with the BJP getting 31 seats and its ally Akali Dal 1 in the 70-member Assembly.
Arvind Kejriwal's Aam Aadmi Party, which had made an impressive debut in last Delhi polls, bagged 28 seats, while the Congress was decimated with its tally plummeting to only 8, its worst-ever performance in Delhi.
Later, Congress supported AAP in government formation but Kejriwal quit as chief minister in February this year over his government's failure to pass the Jan Lokpal bill pushing the state under President's rule.

Banking on Narendra Modi's "wave", BJP is hoping to increase its tally while AAP, which faced strong criticism after Kejriwal quit as Chief Minister, is trying to hard to gain its lost ground.
While the view in Congress is that it may not be in a position to form government, it will better its tally from the previous polls.
The party is also, in a departure from the existing practise, releasing the first list of candidates much in advance this time.

Latest News from States News Desk