The Congress has lodged a complaint with the Election Commission, alleging that BJP president JP Nadda violated the model code of conduct by "canvassing" for his party's Mandar bypoll nominee at a tribal rally, which was supposed to be a "non-electoral" programme.

Addressing the 'Dharti Aba Birsa Munda Vishwas' rally at Ranchi's Morabadi ground on Sunday, Nadda attacked the JMM-led coalition in the state and gave a clarion call to oust the dispensation, which is headed by someone who has become "synonymous with corruption".

"The BJP organised the tribal rally when the nomination process for the bypoll is underway. The appeal made by the BJP national president in favour of his party's candidate was a violation of model code of conduct," Congress spokesperson Rajiv Rajan told reporters after filing the complaint with the office of the chief electoral officer on Monday.

He also said the Congress, a part of the ruling coalition, wanted to know whether the BJP sought permission from the CEO's office to organise the programme which was supposed to be a "non-electoral" event.

BJP has fielded Gangotri Kujur, while Congress nominated former MLA Bandhu Tirkey's daughter Shilpi Neha Tirkey for the by-election.

The bypoll to the assembly seat was necessitated after Bandhu Tirkey was disqualified as a member of the Jharkhand assembly on April 8, following a judgment by a special CBI court.

The special CBI court had on March 28 sentenced Tirkey, a former minister in the state government, to three years in jail in a corruption case. The nomination process for the bypoll ended on Monday.

As many as 19 candidates filed their nomination papers for the by-election and these documents will be scrutinised on Tuesday.

The bypoll will be held on June 23 and votes will be counted on June 26.