The Ministry of Health reported 619 new deaths of patients with Covid-19 on Sunday, a new increase after Saturday's figure had been the best in 19 days.
In total, according to official statistics,16,972 people have now died in Spain since the beginning of the health crisis.
The new increase in new deaths could be due to a backlog in registration due to the public holidays.
Sunday's figure showed an increase of 4,167 new confirmed cases of infection, down on the rise of 4,830 reported on Saturday, taking the new total for Spain up to 166,019
Return to work
Despite recent downward trend in infection, the World Health Organization (WHO) continues to warn of the "danger" of relaxing containment measures too soon.
This comes as thousands of workers not considered essential in the previous extension of the state of alarm, and who cannot take advantage of working from home, are set return to work from this Monday after two weeks off.
As a result, the government has developed a "guide of good practices in the workplace" in which it recommends avoiding, for example, crowding in public transport, disinfecting your mobile phone and glasses when you return home and leaving your shoes at the front door.
Asked about this on Saturday, the head of the Health Alert Coordination Centre, Dr María José Serra, said that despite the return of these workers, the monitoring committee believes that measures in place "will continue to decrease cases of infection".
One such measure is the distribution of ten million masks across "the most important public transport hubs in the country" from the start of next week, as announced by the Minister of Health, Salvador Illa. This will be carried out by state security forces, regional and municipal police and members of Civil Protection. They will also be checking if trips are absolutely necessary.
"We are not deconfining, we are following the recommendations of the WHO and maintaining a very hard confinement," explained Illa.