U.N. chief Ban Ki-moon hit out yesterday at what he called "increasingly restrictive" refugee policies in Europe as the continent faces its worst migrant crisis in decades.

"I am concerned that European countries are now adopting increasingly restrictive immigration and refugee policies," Ban said in a speech to the Austrian parliament. "Such policies negatively affect the obligation of member states under international humanitarian law and European law." His comments came a day after the Austrian parliament adopted one of Europe's toughest asylum laws, as the country's political leaders struggle to halt the surging far-right, which is leading in presidential polls.

The hotly disputed bill, which passed by 98 votes to 67, allows the government to declare a "state of emergency" if migrant numbers suddenly rise and reject most asylum seekers directly at the border, including those from war-torn countries like Syria. If the mechanism is triggered, border authorities will only grant access to refugees facing safety threats in a neighboring transit country or whose relatives are already in Austria. Some groups including minors and pregnant women will be exempt from the rule.

The restrictions are similar to tough rules introduced by the right-wing government in neighboring Hungary last year. In addition, MPs also voted to restrict existing asylum laws by placing limits on the length of asylum granted to migrants and making it harder for their families to join them.

Opposition parties and rights groups slammed the legislation, with the U.N.'s refugee agency warning that it "removes a centerpiece of refugee protection." But Interior Minister Wolfgang Sobotka insisted Austria had no other choice as long as "so many other European Union members fail to do their part" to stop the influx.

Under Austria's new law, the "special measures" will also force migrants to request asylum directly at the border in yet-to-be-built registration centers, where they may be held for up to 120 hours while their application is being checked.

The restrictions are similar to tough rules introduced by the right-wing government in neighboring Hungary last year. Shortly before the vote, a group of protesters threw leaflets from the parliament's upper gallery reading "Don't walk over dead bodies, it won't keep you afloat."

The vote comes after far-right Freedom Party (FPOe) candidate Norbert Hofer sent shockwaves through the political establishment by winning the first round of the presidential election on Sunday. The two candidates of the ruling centrist coalition failed to even make it into the runoff on May 22. The FPOe also looks set to do well in the next scheduled general election in 2018. Trying to stem voter desertion to the far-right, Austria erected border fences and introduced an annual cap on asylum-seekers. It also pressured other countries along the Balkan trail to close their frontiers earlier this year, effectively shutting the route to migrants.

The clampdown has left some 54,000 migrants stranded in Greece and pushed people smugglers to seek out new routes into Europe. More than 26,000 migrants have landed on Italy's shores so far this year after setting off from Libya.

The arrivals have prompted Austria to announce plans to reinstate border controls - including a 370-metre (1,200-foot) fence - at the Brenner Pass in the Alps, a key transport corridor between northern and southern Europe.

The move has sparked protests at the checkpoint in recent weeks and drawn strong condemnation from Italy. "We're very far from an invasion," Foreign Affairs Minister Paolo Gentiloni told Austrian newspaper Die Presse on Wednesday.

Wedged between Europe's two main refugee routes - the Balkans and Italy - Austria received around 90,000 asylum requests in 2015, the second-highest in the bloc on a per capita basis.

More than a million people, primarily from Syria, Iraq and Afghanistan, landed in Europe last year, triggering the continent's worst migration crisis since the aftermath of World War II.

Several European countries have witnessed a spike in Islamophobia and anti-migrant sentiment, especially after an unprecedented influx of refugees, who are mostly Syrians fleeing war and violence. Europe's populist right also rushed to demand an end to the influx of refugees from the Middle East in the wake of the attacks. Recently, polls indicated a rise in support for right-wing parties in France, Austria, Poland and Switzerland. Several European leaders have drawn criticism for their remarks, being accused of xenophobia and racism. Similarly, anti-migrant and anti-Islamic movements such as the Patriotic Europeans Against the Islamization of the Occident (PEGIDA) have been on the rise.