Bangladesh's former premier Khaleda Zia on Thursday alleged that "fascist collaborators" are still conspiring to undermine the achievements of the July uprising and called for a national election acceptable to all to restore the democratic system in the country.

Her son and the Acting Chairman of the Bangladesh Nationalist Party (BNP), Tarique Rahman, asked the interim government led by Muhammad Yunus to maintain neutrality, saying public doubt over its impartiality continues to grow.

Zia, who served as the premier for three terms, in a pre-recorded video address to her party workers said the "fascist collaborators remain active in their schemes" and urged everyone to work together to restore democracy in Bangladesh.

"The fascist ruler fled in a mass movement. The people expect that the current interim government will quickly complete the minimum reforms to repair the state and hold an election acceptable to all to return to the democratic system," said Zia, who is in London for medical treatment.

"Let us invest all our strength to build a democratic Bangladesh. Let us further accelerate unity," the 79-year-old said.

"Although I'm in the UK for treatment, I'm always beside you," she added.

The comments came as leaders of the Anti-Discrimination Student Movement or Students Against Discrimination (SAD), which led the July uprising toppling longtime premier Sheikh Hasina, are set to float a new political party on Friday.

Addressing the meeting attended by around 4,000 party workers and leaders, acting BNP chairman Rahman asked the interim government to maintain neutrality.

"Concerns over its (govt's) impartiality have already emerged among the people. I urge the government to be more vigilant in upholding neutrality," he said, while speaking from London through a virtual platform.

Rahman urged the people to remain alert as "evil attempts continue to destroy the national unity that was built on blood-soaked streets and the electoral atmosphere".