"All Acts by this illegitimate government are illegal and won't last long," she told a programme on Monday night at her Gulshan office.
She was responding to recent comments on her husband Ziaur Rahman by Awami League chief and Prime Minister Sheikh Hasina.
Hasina alleged BNP founder Zia's family was a "murderous one" and that the former president was involved with the assassination of Bangladesh's founding father Sheikh Mujibur Rahman.
She claimed Khaleda, her son Tarique Rahman and Cabinet members were associated with the Aug 21, 2004 grenade attack on an Awami League rally, aimed at eliminating her.
Khaleda criticised the broadcast policy saying it aimed at "controlling the media", an allegation the ruling party has been denying outright.
"The Awami League has illegally occupied power and enacting laws one after the other.
"And now, they are going to hand over power to impeach judges to the illegitimate Parliament to establish control over the judiciary," she alleged.
The Cabinet on Aug 18 accepted a proposal to amend the Constitution allowing Parliament to sack Supreme Court judges.
Law Minister Anisul Huq argued the move was to hold the judiciary to account and ensure transparency in its workings.
"Laws are different for the opposition party and the government now.
"But the government plans to hand over impeachment power to Parliament only to shield its misdeeds," alleged the former prime minister.
The BNP chief warned that the result of making such laws would not be pleasant and urged her supporters to strengthen the party for agitations against the government.
"Be united, focus on the organisation," she told her supporters.
"The next election will be organised under a non-party caretaker government and the Awami League will have to leave."
About the Awami League leaders questioning the BNP's capability to organise a movement, Khaleda retorted, "They say we don't know how to demonstrate.
"It was us who forced Ershad to quit through agitation in the '90s. The Awami League had sided with Ershad and now, they are living on lies."
Monday's programme was organised to exchange views with the BNP-endorsed Upazila Parishad elections winners in Rangpur Division.
In eight districts of the division, candidates loyal to the BNP won 24 chairman, 14 vice-chairman, and 24 female vice-chairman posts in 58 Upazilas.
Khaleda lauded the winners.
"You are the true public representatives as there are no elected representatives in Parliament.
"Work for the people with honesty," she advised them.
'Mujib was freed because of Zia'
Despite criticism by Prime Minister Hasina and Awami League leaders, Khaleda again claimed it was her husband who ‘proclaimed independence’.
"You criticise Ziaur Rahman right and left but [remember,] this Ziaur Rahman saved the people of this country by declaring independence.
"Sheikh Mujib's release from Pakistan prison would have been in doubt had Ziaur Rahman not proclaimed independence and Bangladesh become free.
Khaleda also spoke of Hasina's claim of being tortured after returning home during Zia's rule.
"Zia sent people to bring Sheikh Hasina back. She was handed over property and valuables, except firearms, worth Tk 330 million at that time, the current equivalent of Tk 35 billion," claimed the BNP chief.
She berated Agriculture Minister Matia Chowdhury and Information Minister Hasanul Haq Inu for their remarks about the BNP founder.
"Matia Chowdhury had once spoken of beating a drum made out of Sheikh Mujib's skin while Inu and his colleagues had suggested dumping Mujib's body in the Bay instead of burying it.”.
"They (Matia and Inu) have become Awami League's friends," the BNP chief said.
