European Union interior ministers gave unanimous backing on Thursday to a plan to grant temporary residency to Ukrainians fleeing the Russian invasion, which should come into force within days.

French Interior Minister Gerald Darmanin described as "important and historic" the backing for a package that would offer Ukrainians rights similar to those of formal refugees for a year, and subject to possible renewal.

The protective measures will apply to Ukrainians and those who had long-term residency or refugee status in Ukraine, sparing them from going through lengthy asylum procedures.

EU Home Affairs Commissioner Ylva Johansson said almost 1 million people had already fled Ukraine, entering EU territory via Poland, Romania, Slovakia and Hungary, but the EU had shown unprecedented unity and ability to act in the past few days.

"Today also, the ministers showed that on a topic that is very usually seen as being toxic or difficult, the migration issue," she told a news conference.

The EU temporary protection mechanism was set up in the 1990s during the conflict in the former Yugoslavia to deal with mass influxes of displaced people. However, it has never so far been triggered.

The scheme proposed by the Commission will automatically grant those fleeing Ukraine a residence permit and access to employment, social welfare and housing for up to three years.

Those on short-term stays in Ukraine would be allowed into EU territory and would get help to make their way home.

Earlier, Hungarian Prime Minister Viktor Orban's chief of staff had sown doubt by saying Hungary and its eastern European neighbours did not support the EU plan but favoured instead the existing EU asylum rules.

Darmanin said the Hungarian minister at the meeting had denied this was the case. A Hungarian government spokesperson said a solution was presented in the afternoon that was acceptable for everyone.

An EU diplomat said there appeared to have been a misunderstanding over the matter in Budapest, but there was unanimity at the ministers' meeting and the proposal was supported.