The country reported 585 new fatalities in the past 24 hours, but it was difficult to compare with previous tolls after the government amended its counting mechanism.
The total number of deaths in Spain now stands at 19,478, the third-highest in the world after the United States and Italy.
The government issued revised guidelines overnight for reporting deaths in order to standardise the data sent in from the country's 17 autonomous regions.
Datos sobre #Coronavirus en España, desde el primer caso inicial, actualizados a día 17 de abril:
— Salud Pública (@SaludPublicaEs) April 17, 2020
The change was an apparent move to eliminate any deaths where the patient had not been tested for covid-19. Officials said they would revise previous fatality counts, and also apply the new rules to death tolls moving forward.
“This could mean that some of the figures may seem a little strange,” said Fernando Simón, the health ministry's emergencies coordinator, pointing to a “discrepancy” in the data supplied by one particular region.
There have been growing questions over the death toll in recent days with Madrid and Catalonia, the two worst-hit regions, this week insisting they had thousands more victims than the official count.
On Wednesday, Catalonia said it would use new criteria by including figures provided by the region's funeral services who count virus victims and those who have died at old people's residences or at home with symptoms compatible with covid-19.
But not all of those victims would have necessarily been tested for the virus.
The overall number of hospitalizations (blue), admittance into ICU (yellow) deaths (red) and recoveries (green) are shown in the chart below, which reveals that the curve of the number of hospital admittances is flattening. Data: Ministry of Health.
'We may never know'
According to this new criteria, the region says it has suffered more than 7,500 deaths, while the ministry's count gives a figure which is some 50 percent lower — 3,752.
Without mentioning Catalonia, Simón on Friday said that the data submitted by one region “did not have the consistency that we would wish to have in a data set”.
Madrid has also challenged the methodology, with its regional government saying this week the number of dead — which by Friday stood at 7,007 — was likely to be more than 10,000.
“More people are dying of coronavirus than officially declared by the Spanish government,” the region's vice president Ignacio Aguado told Spain's RNE radio.
“In many cases, unfortunately, they have been unable to do a test… even though everything indicated that they had covid-19.”
He added that the “number of dead is much higher” because only people who died in hospital and tested positive are being counted in the national tally.
“We'll never know the real number (who have died) during this tragedy,” he added.
Friday's toll was the highest daily figure since Sunday when 619 people died in 24 hours.
The data also revised down the number of people who had recovered from covid-19, giving an overall total of 72,963, from the previous estimate of nearly 75,000.
But the number of infection did correlate with earlier figures, showing an increase of 5,252 new cases, bringing the overall total to 188,068.