The ECB is due to unveil its new projections on Dec 10, along with a new stimulus package. De Guindos' comments suggest a cut to the inflation forecast for this year, next year and possibly even 2022 is on the cards.
"Inflation will be negative until the end of the year and we expect that it will turn positive next year," de Guindos told Finnish newspaper Helsingin Sanomat. "All in all, we expect inflation to be close to 1% in 2021 and to see it moving up towards 1.2% or 1.3% in 2022."
Christine Lagarde's deputy also confirmed consensus expectations for a contraction in the euro zone economy this quarter but said the prospect of a vaccine against the novel coronavirus meant the outlook further out appeared brighter.
"Negative quarter-on-quarter growth is now the most realistic scenario for the end of the year," de Guindos said.
"But the medium-term outlook - mainly because of the ray of hope brought by news of the vaccine - looks brighter."
In September the ECB said it saw euro zone inflation at 0.3% in 2020, 1.0% in 2021 and 1.3% in 2022 while it expected real GDP to fall by 8.0% this year before rebounding by 5.0% in 2021 and by 3.2% in 2022.
The central bank has said it will announce the terms of its new stimulus package, mainly consisting of more bond purchases and subsidised loans to banks, at its December meeting.
(Reporting By Francesco Canepa; Editing by Kirsten Donovan)