The environment is the top concern for voters in Sunday's snap polls in the small Alpine nation of 8.8 million people, according to surveys.

Amid a rash of other voter-friendly measures, MPs from all parties except the far-right Freedom Party (FPOe) supported the resolution for the largely symbolic measure, already adopted by many other national parliaments and cities.

FPOe lawmaker Walter Rauch dismissed the declaration as an attempt to create "climate hysteria far removed from any reality".

All parties -- including the FPOe which ruled the country as junior coalition partner to then chancellor Sebastian Kurz until a corruption scandal in May -- have taken up the promise to protect the environment in their campaigns.

In Sunday's polls, Kurz's People's Party (OeVP) is expected to be the strongest again, while the Greens -- who failed to get into parliament in the last elections in 2017 -- are tipped to make the biggest gains.

Austria is seen as a pioneer in several fields, such as organic farming and renewable energies.

But it falls short in terms of greenhouse gas reduction.

Between 1990 and 2017, Austria together with five others were the only EU members who saw their greenhouse gas emissions continue to increase, while in the whole union they have fallen by 22 percent.

Britain's parliament became the first in the world to declare a climate emergency, passing the motion on May 1.

According to The Climate Mobilization, a US NGO pushing for such declarations, more than 1,000 local authorities in cities and towns across the world have now declared a climate emergency.