The city's Governor says more than 200 people are now believed to have been killed as a result of the August 4 blast, which occurred when a stockpile of more than 2,000 tonnes of ammonium nitrate exploded.

Many Lebanese blamed the Government for allowing the material to be stored in Beirut's port for seven years, and are angry at what they regard as corruption in the country's political establishment.

The explosion destroyed swathes of the bustling Mediterranean capital, injured over 6,000 people and compounded months of political and economic meltdowns in Lebanon.

Mr Diab, in a speech televised on Monday (local time), said the disaster was "the result of endemic corruption".

He said he was taking "a step back" so he could stand with the people "and fight the battle for change alongside them".

"Today we follow the will of the people in their demand to hold accountable those responsible for the disaster that has been in hiding for seven years, and their desire for real change," he said.

"In the face of this reality … I am announcing today the resignation of this Government."

A televised announcement afterwards said Lebanese President Michel Aoun had accepted the resignation and asked the Government to stay on in a caretaker capacity until a new Cabinet could be formed.

For many ordinary Lebanese, the explosion was the last straw in a protracted crisis over the collapse of the economy, endemic corruption, waste and dysfunctional governance, and they have taken to the streets demanding root-and-branch change.

Anti-government protests in the past two days have been the biggest since October, when angry demonstrations spread over an economic crisis rooted in pervasive corruption, mismanagement and high-level unaccountability.

Protesters accused the political elite of siphoning off state resources for their own benefit.

Mr Diab blamed corrupt politicians who preceded him for the "earthquake" that has hit Lebanon.

"They [the political class] should have been ashamed of themselves because their corruption is what has led to this disaster that had been hidden for seven years," he added.

"I have discovered that corruption is bigger than the state and that the state is paralysed by this [ruling] clique and cannot confront it or get rid of it," said Mr Diab, who was a professor at the American University of Beirut before he took the job.

The resignation of the Government typified Lebanon's political dilemma.

The ruling oligarchy has held onto power for so long — since the end of the civil war in 1990 — that it is difficult to find a credible political figure untainted by connections to it.

Mr Diab's Government was formed after his predecessor, Saad Hariri, stepped down in October in response to the demonstrations. It took months of bickering among the leadership factions before they settled on Mr Diab.

His Government, which was supported by the Hezbollah militant group and its allies and seen as one-sided, was basically doomed from the start, tasked with meeting demands for reform but made up of all the factions that reformers want out.

Public Works Minister Michel Najjar said he hoped the caretaking period would not be long "because the country cannot take that".

"Let's hope a new government will be formed quickly," Mr Najjar said.

"An effective government is the least we need to get out of this crisis."