Gono Forum President Dr Kamal Hossain urged the government to accept seven-point demand of Jatiya Oikyafront in due time.
He also threatened to bring the government to justice in future if it does not accept the demands.
"People gave their verdict in favour of the seven-point by raising their hands today. A mass verdict was also given in Sylhet in this regard. We would like to tell the government to accept the demands before time runs out. Or else, you will have to face trial," he said.
Dr Kamal came up with the statement while addressing a public meeting organised by the new alliance in front of BNP's Chattogram office on Saturday, report UNB and bdnews24.com.
On October 13, BNP together with Dr Kama Hossain-led Jatiya Oikya Prokriya, JSD and Nagorik Oikya launched the Jatiy Oikyafront to press for their seven-point demand.
Dr Kamal said the government will be forced to accept their alliance's seven-point demand, including holding the next polls under a non-party government and dissolution of parliament, as people have got united.
"There's nothing impossible to achieve when people get united as we had proved it in the past, including during the Liberation War," he added.
The veteran politician accused the government of 'regularly' overriding the constitution, and warned that it has to be accountable to people for it one day.
Dr Kamal also said the government will have to face trial for harassing people by implicating in 'false' cases.
He criticised the government for not releasing BNP chairperson Khaleda Zia from jail.
The rally activities started around 1:30pm on Saturday with recitation from the holy Quran and holy Gita.
Chattogram city unit BNP president Dr Shahdat Hossain presided over the rally.
BNP secretary general Mirza Fakhrul Islam Alamgir, JSD President ASM Abdur Rob, Nagorik Oikya convener Mahmudur Rahman Manna and other Oikyafront leaders addressed the rally.
Before the beginning of the rally, senior leaders of the Oikyafront visited the shrine of Hazrat Shah Amanat (R) and offered fateha there.
This was the second rally of the newly formed alliance as it held its maiden one in Sylhet on October 24.
Several hundred leaders and activists of the party holding placards, banners and portraits of BNP founder Ziaur Rahman, chairperson Khaleda Zia and acting chairman Tarique Rahman started gathering at the rally venue since noon.
Huge law enforcers were deployed around the rally venue to maintain law and order.
The Oikyafront's seven-point demand includes installation of a neutral interim government, dissolution of parliament, reconstitution the Election Commission, release of all the political prisoners, deployment of army and cancellation of the move to use Electronic Voting Machines (EVMS) for holding the next polls in fair and acceptable manner.
However, the ruling Awami League has rejected all the demands.