Spain's economy has been growing faster than the eurozone average this year after recovering from the Covid-19 crisis, providing vital political oxygen to the often beleaguered minority left-wing government.

But the October 29 catastrophe washed away roads and rail lines, submerged fields and gutted homes and businesses in the European Union's fourth-largest economy.

The final bill is expected to soar to tens of billions of euros.

"The estimated impact would be close to -0.2 percentage points on the quarterly growth rate in the fourth quarter," Bank of Spain governor Jose Luis Escriva told reporters in Madrid.

He added that the estimate is based on what happened after Hurricane Katrina ravaged the US Gulf Coast in 2005, killing more than 1,800 people.

While the devastation caused by the floods did not reach the "levels" seen in the wake of Katrina, "the dynamics are very similar," Escriva said.

The disaster wreaked the most damage and deaths in the eastern Valencia region, one of Spain's industrial and agricultural powerhouses which is home to one of Europe's busiest cargo ports.

Some of the hardest-hit areas were residential towns in the industrial belt around Valencia, Spain's third-largest city, which disrupted economic activity there, Escriva said.

The Spanish economy expanded by 0.8 percent in the third quarter thanks to rising exports and domestic consumption, outperforming forecasts by the Bank of Spain.

The government in September revised its forecast for GDP growth in 2024 up to 2.7 percent from 2.4 percent. It has so far not changed its estimates in the wake of the floods.

Observers including the International Monetary Fund have also revised upwards the country's growth prospects, with credit ratings agency Fitch predicting around three percent in 2024 and over two percent in the following two years.