Maharashtra BJP chief Chandrakant Patil on Saturday said the swearing-in of the Uddhav Thackeray-led ministry was illegal as the prescribed format of oath was not adhered to.
Ministers, while taking an oath, took names of their leaders and others, which was not as per the protocol, Patil told reporters at the legislature complex here.
A petition is being filed before Governor B S Koshyari against the "illegal" oath-taking ceremony, he said.
The former minister also alleged that the government defied rules in replacing BJP's Kalidas Kolambkar with NCP's Dilip Walse Patil as pro-tem Speaker, and questioned the propriety of holding an election for Speaker's post after the floor test.
Thackeray-led Shiv Sena-NCP-Congress government won the floor test on Saturday after the BJP MLAs walked out.
The election for Speaker's post will be held on Sunday.
Thackeray and two ministers each from the Shiv Sena, NCP and Congress took oath on November 28 at a ceremony at Shivaji Park here.
The leaders mentioned their respective party leaders such as Sena founder Bal Thackeray, and also iconic figures such as Shivaji Maharaj and B R Ambedkar while taking oath.
"The new government has defied state legislature rules right from its swearing-in ceremony," Patil said.
"We have faith in late Balasaheb Thackeray, Chhatrapati Shivaji Maharaj, Babasaheb Ambedkar. But oath has to be taken in a particular format. It is not considered an oath if it is not taken in that format. A petition is being filed before Governor contending that the swearing-in was illegal," he added.
The BJP leader did not name which MLA would be filing the petition, but said the legislator was not from his party.
NCP spokesperson Nawab Malik rubbished Patil's allegation, saying many BJP MPs did the same thing when they were sworn in.
"If Patil's yardstick is to be used, half the Lok Sabha will be empty," he added.
Patil, meanwhile, also said that people had voted for BJP-Shiv Sena alliance which got 161 seats, "but the Shiv Sena betrayed the mandate".
"Since the first press conference (after the poll results came on October 24) they had started talking about alternatives."
Patil also claimed that the government flouted rules in replacing Governor-appointed pro-tem Speaker Kalidas Kolambkar.
"Till now Assembly Speaker was elected first and then the floor test was conducted. But now, trust vote is being carried out today and the Speaker's election is to be held tomorrow.
"As per the law, Speaker is elected through secret ballot. They are now thinking of conducting the Speaker's election openly. This is in violation of laws and rules of the legislature," he said.
BJP MLA from Murbad, Kisan Kathore, will be the party's its candidate for Speaker's election, he said.
The Congress has named its Sakoli legislator Nana Patole as candidate of the ruling alliance for the post.
Ahead of the floor test -- which the ruling combine eventually won -- the Shiv Sena, NCP and Congress issued whips to their MLAs to remain present in the House.
Chief minister Uddhav Thackeray paid tributes to Shivaji Maharaj on Vidhan Bhawan premises ahead of the floor test.