The October 29 disaster claimed 224 lives nationwide -- 216 in the eastern Valencia region -- wrecked infrastructure, gutted buildings and submerged fields in damage costing tens of billions of euros.

Outrage at the authorities for their perceived mismanagement before and after the floods has coursed through Spain, piling particular pressure on the Valencia region's conservative leader Carlos Mazon.

"I'm not going to deny mistakes" or "shirk any responsibility", Mazon told Valencia's regional parliament on Friday in a monologue lasting around two hours.

Many residents living in towns soaked with mud have complained they were left without food and water for days and relied on volunteers instead of the government for aid.

As regional president, "I would like to apologise" to those who felt "the aid did not arrive or was not enough," Mazon added.

As he spoke, dozens of protesters gathered outside the building, jeering and chanting slogans demanding his resignation and calling him a liar.

The Socialist central government has insisted urgent rescue and reconstruction work must take precedence over investigating the state's shortcomings and demanding immediate political accountability.

But the Socialist party appeared to break with that line on Friday, demanding that Mazon's conservative Popular Party depose him, form a new regional government to focus on the recovery and hold early elections next year.

Mazon said he would "lead this recovery with full determination" and not stand for re-election in 2027 if he failed.

- Recriminations -

In Spain's decentralised state, regional governments lead disaster response, but the authorities in Madrid can supply resources and take charge of the management in extreme cases.

Critics have questioned the efficiency of the Valencia region's alert system, which in some cases only reached residents' telephones when floodwater was already gushing through towns.

The Socialist-led central government has said Mazon's conservative-run administration bore responsibility for not issuing the alert earlier.

But Mazon on Friday criticised those who "hide behind" interpreting the division of powers and "the small print of laws" to avoid examining themselves, without naming anyone.

He said he accepted "my responsibility" and called on Prime Minister Pedro Sanchez to be "up to the task".

Mazon has also come under fire for having been missing for several critical hours on the afternoon of the disaster when it was already raining heavily.

In response to repeated questions for explanations for his absence, he finally admitted he had been having lunch with a journalist to offer her the directorship of the regional television station.