Pakistan's Opposition parties on Thursday observed a "Black Day" on the first anniversary of the parliamentary elections that brought Prime Minister Imran Khan into office and lashed out at his government for its failure to address the problems of the people.

Big rallies were organised in Karachi, Lahore, Peshawar and Quetta and a demonstration held in the capital, Islamabad.

Maryam Nawaz, daughter of jailed former prime minister Nawaz Sharif, addressed a rally in Quetta, the capital of Balochistan. She lambasted the government for failing to address the problems of the people.

She urged the powerful institution not to support the government of Imran Khan.

"You are not the institutions of Imran Khan. You are not the representatives of the man who brought historical failure to Pakistan," she said.

"Don't pick a fight with the people for the incapable and failed Imran Khan," she said while refraining from naming any institution.

Shehbaz Sharif, Leader of Opposition in parliament and the president of Pakistan Muslim League-Nawaz (PML-N) led a rally in Lahore.

"The nation has come to know the lies and fraud as well as the inefficiency of (Imran Khan). By imposing restriction on media, the 'selected ruler' is only acknowledging his frustration and incompetence," he tweeted.

Bilawal Bhutto Zardari of the Pakistan Peoples Party (PPP) addressed a rally in Karachi and tore through the policies of the government.

The mainstream media avoided coverage of the protests in what seemed to be an unannounced censorship.

However, social media platforms were flooded with clips of speeches by the Opposition leaders in all major cities.