The UK government decision to advise against all but essential travel to the whole of Spain was "unjust", the country's prime minister has said.
Pedro Sanchez said Britons would be safer from coronavirus in most regions than they would be in the UK, and negotiations were taking place.
It comes after the UK decided to impose a two week quarantine on travellers returning from anywhere in Spain.
Labour said the government's handling of the restrictions had been "chaotic".
But the UK government said it has no plans to change its decision to reintroduce the quarantine measures from last Sunday - with Boris Johnson's official spokesman warning that "no travel is risk-free during this pandemic".
On Monday, the UK also extended the travel advice for Spain, now advising people to avoid non-essential journeys to the Canary and Balearic Islands, as well as mainland Spain.
In an interview on Spain's Telecinco TV network, Mr Sanchez said he was hoping to convince the UK government to rethink its decision to remove Spain from the list of countries exempt from quarantine rules.
"We are talking with British authorities to try to get them to reconsider a measure that, in our opinion, is not well adjusted if we consider epidemiological criteria of Spain, particularly in some tourist destinations in our country."
He said the UK had made an "error" by considering the infection rate for the whole country.
Spain's prime minister added that "64.5% of the new cases registered are in two territories" and in most of Spain the prevalence of Covid-19 was "very much inferior to the numbers registered in the United Kingdom".
The rate of infection in Spain is 35.1 cases per 100,000 people, while the UK is at 14.7, according to the latest figures from the European Centre for Disease Prevention and Control.
While the outbreak remains under control in many parts of Spain, certain areas - in particular Catalonia in the north-east and the neighbouring region of Aragón - have seen a huge spike in infections.
Data up to 19 July suggested there were lower rates of infection in the Balearic and Canary Islands than in mainland Spain.
Travellers returning to the UK from anywhere in Spain must now self-isolate for 14 days at a registered address.
Among the thousands affected by the change in travel advice was Tom Clasby, who had checked into an airport hotel near Stansted with his fiancé, their two daughters, and other family members, ahead of a holiday to Majorca.
Mr Clasby, 26, was due to depart at 06:55 BST on Tuesday but now faces having to return home to Bury St Edmunds.
"We're in a situation where we can't do anything yet and I don't actually know what to do. The poor little girls have been so excited for this holiday - it's the second holiday this year we've had cancelled," he told the BBC.
"We are just very disappointed, the girls will be so upset in the morning."Image copyright Tom Clasby Image caption Tom Clasby said he was dreading telling his two daughters their Spanish holiday was cancelled
Also affected was Transport Secretary Grant Shapps, who flew to Spain on Saturday despite knowing a decision on the quarantine policy was due.
Mr Shapps said in a statement he would return to the UK on Wednesday in order to complete his quarantine and would return to work as soon as possible.
Holiday companies Jet2 and Tui were among those to announce sweeping flight cancellations following the UK announcement.
EasyJet, British Airways, and Ryanair said they would continue to operate full schedules of flights to Spain, though EasyJet said its holidays would be cancelled for the next few weeks.
Labour has urged the government to step in to protect jobs in the travel industry.
Shadow transport secretary Jim McMahon said: "The government's handling of this issue has been nothing short of chaotic. The airline industry and passengers need clarity."
He added that the government "must focus support on the sectors that desperately need it, like aviation".
Meanwhile, the Foreign Office has been criticised by MPs over its response in helping more than a million Britons travelling abroad at the start of the pandemic.
The Foreign Affairs Committee said the repatriation operation had been too slow, whilst advice had been misleading or confusing.
It comes as a further seven people with coronavirus were reported to have died across all settings in the UK, according to latest government figures - bringing the UK's total number of deaths to 45,759.
In other developments:The leader of the World Health Organization said Covid-19 is easily the most severe global health emergency it has ever declared Campaigners have written to the health secretary to say a lack of translated coronavirus guidance is jeopardising the safety of non-English speakers in the UK A report from the Commons Home Affairs Committee says stronger action needs to be taken to protect people in asylum accommodation from the risk of coronavirus. MPs say the use of shared rooms makes it "extremely difficult" for people to keep to social distancing Republicans have proposed spending an additional $1tn (£776bn) to address the economic damage caused in the US by the pandemic