Former prime minister Atal Bihari Vajpayee on Tuesday said the Congress-led coalition at the Centre was becoming 'increasingly unstable', and asked party leaders to remain prepared for the possibility of mid-term elections.

"Whether mid-term elections are held or not, we should remain prepared and remain in constant touch with the people," Bharatiya Janata Party deputy leader in the Lok Sabha VK Malhotra quoted Vajpayee as saying.

Vajpayee was addressing the last parliamentary party meeting of the Monsoon Session.

Leader of Opposition and party president Lal Kishenchand Advani termed as 'wrong, mischievous and baseless' United Progressive Alliance chairperson Sonia Gandhi's [Images] charge that the Opposition changed its stand on the Women's Reservation Bill.

Advani said Gandhi was trying to blame the BJP for the UPA's "failure" to evolve a consensus on the Women's Reservation bill with some of its allies even threatening to 'physically prevent it'.

Advani also expressed satisfaction over the 'constructive role' of the opposition in the Monsoon Session and said they were successful in driving home their point.

With the proposal to enhance the number of seats appearing to be "impractical", the party felt that the Election Commission's suggestion that political parties distribute 33 per cent tickets to women seemed more practical, Malhotra said.

The parliamentary party also decided to oppose any attempt on the government's part to bring the Illegal Migrants Determination Tribunal through the back door, hike petroleum prices and introduce foreign direct investment in retail trade.