The Maharashtrawadi Gomantak Party, a Bharatiya Janata Party ally in Goa, gave an ultimatum on Saturday that the charge of the chief minister's post be given to its minister Sudin Dhavalikar in view of Manohar Parrikar's illness.
The MGP warned that it would contest the Lok Sabha polls and assembly by-elections in the state against the BJP candidates if the demand was not met.
Parrikar, who is suffering from a pancreatic ailment, is recuperating at his residence since October 14 after being discharged from the All India Institute of Medical Sciences in New Delhi.
Two assembly seats -- Mandrem and Shiroda -- fell vacant last month after respective MLAs, Dayanand Sopte and Subhash Shirodkar, resigned as legislators and quit the Congress to join the BJP.
"Party's central committee had a detailed discussion on the leadership issue today. Chief Minister Manohar Parrikar is ailing and, because of that, the administration is completely paralysed for the last eight months," MGP president Dipak Dhavalikar said.
"Therefore, to bring in discipline and efficiency to the administration, we demand that the chief minister's charge be given to senior MGP MLA Sudin Dhavalikar as early as possible," he said.
"If the charge is not given immediately, we will contest all upcoming elections, that is (assembly) by-election and Lok Sabha polls, by fielding our candidates against official candidate of the government," he said.
Sundin Dhavalikar is presently the second-most senior minister in Goa cabinet after Parrikar.
MGP's central committee will meet again next month to review the situation, Dipak Dhavalikar said.
"We will see if the government has taken our warning seriously or has continued with the same situation," he said, adding that he himself might contest the by-election from Shiroda, while the party would support independent MLA Jit Arolkar in Mandrem.
The MGP is part of the BJP-led coalition, which also includes Goa Forward Party and three independents.
Meanwhile, the Congress demanded that Goa Governor Mridula Sinha summon a special session of the legislative assembly and ask the BJP-led coalition government to prove its majority.
The opposition party, which has been claiming that the state government is in disarray in the absence of ailing Parrikar from office, alleged that it "is a classic case of fraud being played on the people of Goa by the Governor and the BJP at the Centre".
Congress chief spokesperson Randeep Singh Surjewala told reporters here that the party would raise this issue during the upcoming winter session of Parliament and also before President Ram Nath Kovind.
The Congress had submitted representations to the President and the Goa Governor, claiming that the party had the requisite number of MLAs to prove majority in the 40-member House.
"We will put pressure on the central leadership of the BJP in winter session and also before the President for our demand to summon a special session to prove majority," he said.
Accusing the ruling Bharatiya Janata Party in Goa of holding the Constitution "captive", Surjewala said the formation of the Cabinet Advisory Committee by the BJP in absence of Parrikar is a "blatant fraud on the Constitution".
Surjewala said the coalition government should prove its majority and lay down a roadmap for governance and administration.
The government should also settle issues like Regional Plan, mining, unemployment, he demanded.
"This will clear all doubts about who is in-charge in Goa and the floor test will determine as to which party has the rightful claim to head a democratic government in people's interest in Goa," he added.
Surjewala questioned the effectiveness of state government in absence of Parrikar, who is currently recuperating at his residence here after undergoing treatment at AIIMS in Delhi.