"The effects of the pandemic have forced us to rethink our planned timeline. This affects the end date we had planned for 2026," said Esteve Camps who heads the Sagrada Familia's construction board, AFP wrote.
One of Spain's top tourist attractions, the towering architectural masterpiece has been under construction for nearly 140 years but the vast project only received a building permit last year.
When finished, the ornate cathedral which was by modernist Catalan architect Antoni Gaudi, will have 18 towers with its highest steeple reaching 172 meters (564 feet) into the air.
It was to have been completed in 2026 – on the 100th anniversary of the death of Gaudi, who was run over by a tram.
"We are not able to propose any new date" for completing the building work which began in 1882, but "it will be impossible (to finish) in 2026", he said.
Construction works came to an abrupt halt in March when the Spanish government ordered a national lockdown to slow the spread of the virus, and will only resume "in the coming weeks", he said.
Even then, the works will resume at a slower pace given the basilica's lack of funds as the cost of its construction is financed by donations from the faithful and the takings from ticket sales to tourists, both of which have plummeted during the crisis.
For now, they only have funds to finish building a huge tower dedicated to the Virgin Mary which will be second highest of the 18 towers that will grace the finished monument.