The Bharatiya Janata Party-led National Democratic Alliance on Friday rejected a renewed appeal by Prime Minister Dr Manmohan Singh to end its boycott of Parliament.

Speaking in the Rajya Sabha on Thursday, Dr Singh had said the opposition would not be prevented from raising any issue on the floor of the House.

The NDA is boycotting Parliament to lodge a protest against, what it calls, 'ill treatment' of the opposition in Parliament.

The alliance is also demanding the resignation of Railway Minister Lalu Prasad Yadav, who has been charge sheeted in a fodder scam case.

NDA leaders met at the residence of former prime minister Atal Bihari Vajpayee in the morning to discuss the prime minister's appeal.

Speaking to reporters after the meeting, senior BJP leader Jaswant Singh criticised the use of strong language by Dr Singh against the NDA leadership.

"We strongly object to the tone and tenor of his statement. First the prime minister had described the opposition's decision to boycott the House as childish and now he has accused us of falsehood. This is like adding insult to the injury," Singh said.

Making the statement in the Rajya Sabha, the prime minister had charged the NDA of making a false accusation that the government had tried to prevent Pakistan President Pervez Musharraf from meeting Vajpayee.

"The government should ensure that there is a healthy and open parliamentary discussions. But the UPA government has shown total disregard for the opposition parties. In fact, they have been carrying on campaign against a senior leader of the NDA, George Fernandes," Singh said.