NCP chief Sharad Pawar on Wednesday asked the party defectors, who quit saying they wanted to ensure development of their constituencies, what they were doing for 15 years when they were in power.
Ahead of Maharashtra elections, the Nationalist Congress Party has seen exit of leaders to the ruling BJP or Shiv Sena.
Mr Pawar, who is on a state-wide tour before the next month's polls, was addressing party workers at Beed on Wednesday.
The Congress and NCP were in power in Maharashtra for 15 years, from 1999 to 2014, before they were ousted by the BJP and Shiv Sena.
"The leaders from this region who deserted the party have said they quit for development. This leads to a question, what were you doing when you were made MLA or state ministers?" Mr Pawar said.
Former ministers Ganesh Naik, Sachin Ahir and Madhukar Pichad are among those who quit the NCP recently. NCP MP from Satara Udayanraje Bhosale joined the BJP on Sunday.
Mr Pawar also alleged that around 16,000 farmers have committed suicide in the state.
Businessmen were getting loan waivers worth thousands of crores of rupees but not the farmers in the country, he said.
"Factories have closed down, farmers are in the middle of crisis and unemployment is on rise. Yet the leaders of the ruling parties are coming to seek votes. Their every scheme has failed. We should resolve not to hand over power to these people again," he said.