Pedro Sánchez has asked for a two-week extension to the national lockdown
Spain will slowly ease its nationwide lockdown in the second half of May, the prime minister said, provided authorities stay "on top of the virus".
Pedro Sánchez asked parliament in Madrid for a third extension to the state of emergency until 9 May.
The government has also announced looser restrictions on children, allowing them to leave the house.
Spain imposed its lockdown on 14 March, with some of the tightest restrictions in Europe.
Currently, children are not allowed outside for any reason. After mounting criticism, the government announced plans on Tuesday to allow those aged 14 and under out for walks from 26 April.
Construction and manufacturing businesses were allowed to resume work last week, albeit under strict new social distancing and safety measures.
Spain currently has the most confirmed coronavirus infections in Europe.
Latest data released on Wednesday show the death toll stands at 21,717, rising by 435 in the past 24 hours - the second consecutive day-on-day rise. The total number of confirmed cases has risen to 208,389.
Addressing parliament in Madrid on Wednesday, Mr Sánchez asked for the state of emergency to be extended for a third time by an additional two weeks.
The prime minister said Spain could then hopefully begin to ease its restrictions in the second half of May, but warned that "de-escalation will be slow".
"We must avoid missteps," he warned. "If we stay on top of the virus and our health system maintains and reinforces that impression, then we will propose another step." Inside the ICU in one of Spain's biggest hospitals
Lawmakers will vote later on the extension. The measure is expected to pass, although some parties, including the far-right Vox and two from Catalonia have said they will not back it.
Mr Sánchez said he expected EU leaders to agree a common economic response to the coronavirus outbreak during a European Council video summit on Thursday.
EU finance ministers agreed to a €500 billion (£440bn; $543bn) stimulus package on 9 April.
Spain, as well as Italy and France, has called for greater support from the EU to finance member states' economic recovery.
The opposition People's Party leader, Pablo Casado, bitterly criticised the Spanish government's handling of the crisis as incompetent, arguing that the state of alarm should have been introduced a week earlier. The microphone in the Spanish parliament had to be disinfected after every speaker
"This is is not a war, as the government likes to compare it to, this is a human catastrophe," he said, adding that his uncle had died and the family were unable to bury him together.
The state of emergency imposed on 14 March had some of the tightest restrictions in Europe - including barring all children from going outside for any reason.
After weeks of confinement, opposition groups, charities and health workers criticised the continuing restriction. Barcelona's mayor Ada Colau took to Facebook, demanding the government "Free our children". Italy has closed its parks during lockdown, but one is opening for children with autism
On Tuesday the government announced its plans to ease restrictions, saying children aged 14 and under could accompany their parents on errands.
But there was anger the authorities had not gone further. People in Madrid took to their balconies to bang pots and pans in protest.
"This is a government that listens and next weekend I will issue an order allowing children under 14 to take walks from Sunday, April 26th," Health Minister Salvador Illa said.
Details about where and for how long they can walk will be released later this week. Children will still need to be accompanied by an adult.
The BBC investigates allegations of exploitation by labourers working in the Spanish fruit and vegetable growing region Almeria
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