Spain's daily coronavirus death toll shot up to 743 on Tuesday after falling for four straight days, bringing the total to 13,798, the health ministry said.
However, it emphasised that the rise was due to weekend deaths being tallied and that the overall "downward trend" is continuing.
The new figure represents a 5.7 percent increase over the 637 deaths recorded on Monday, the lowest number of fatalities since March 24 in the world's second hardest-hit country after Italy in terms of fatal outcomes.
The number of new infections also grew at a faster pace, rising 4.1 percent to 140,510, the health ministry said. The number of new cases rose 3.3 percent on Monday.
The "slight" rise was due largely to the fact that many deaths and new infections which occur over the weekend are only now being recorded, said Maria Jose Sierra of the health ministry's emergencies coordination unit.
"In reality the downward trend is what we continue to observe in the reports we have received in recent days," she told a daily news conference on the figures.
Spain had seen the number of new infections and deaths drop each day since it recorded a record 950 fatalities on Thursday.
The percentage increase in the number of deaths is far lower than the 32.63 percent leap recorded as recently as March 21.
The number of people in hospital intensive care units also continues to fall, Maria Jose Sierra added.
Mari Angels Rodriguez, a nurse at the Hospital Josep Trueta hospital in Girona in northeastern Spain, said the number of patients had "dropped significantly" over the past two weeks.
But intensive care units (ICUs) were still overloaded because coronavirus patients spend an average of 14 days in them, she added.
"Each new patient occupies a bed for a long time," Rodriguez told AFP.
Eduardo Fernandez, a 39-year-old nurse at Madrid's Infanta Sofia Hospital, also said there had been fewer admissions in recent days.
"But we remain much above or usual capacity," he added.
"I don't know if my colleagues who are in the eye of the storm are able to see (the decrease) because the work pressure is very high."
Spain, a nation of around 47 million people, has imposed one of the strictest lockdowns in Europe to try to curb the spread of the virus.
Since March 14 people have been banned from leaving their homes except to buy food, get medical care, briefly walk their dog and go to work if they can not do their job remotely and it is deemed an essential service.
The head of Spain's National Police force, Jose Garcia Molina, said officers had noticed in recent days that more people were violating the lockdown rules, and warned enforcement would be stepped up during the upcoming Easter holidays.
"We have identified people who travelled several kilometres to buy bread, who were visiting non-existent relatives and a man who, with the excuse that he was walking his dog, went for a more than 45 minute walk on the beach," he said.
Police have arrested nearly 1,500 people for not respecting the rules since the lockdown began, he added.