Patrick KingsleyMigration correspondent Thursday 28 April 2016 11.41 BST

UN secretary general speaks in Austrian parliament a day after Vienna passes law allowing police to reject asylum seekers at border

The UN secretary general, Ban Ki-moon, has hit out at “increasingly restrictive” European asylum policies in a speech to the Austrian parliament, which has voted to bring in some of the continent’s most stringent laws after a far-right politician won the first round of presidential elections.

Ban did not name any country in his speech but, considering the venue, his comments appeared to allude at least in part to ongoing Austrian moves to tighten its border controls and reduce the entry of asylum seekers.

“I am concerned that European countries are now adopting increasingly restrictive immigration and refugee policies. Such policies negatively affect the obligation of member states under international humanitarian law and European law,” he told MPs.

The parliament’s lower house voted on Wednesday in favour of a law that will allow police to reject asylum seekers at the border and to stop most successful applicants from applying to be reunited with their families for three years.

The law must still be passed by Austria’s second parliamentary chamber on Thursday, but since this is a formality, the interior ministry expects to begin enforcing the law at the start of June.

Under the terms of the law, the Austrian government will be able to declare a state of emergency in times of significant irregular migration. Once this mechanism is triggered, “irregular migrants” at the Austrian borders will be sent immediately back to the countries they arrived from, on the assumption that Austria’s neighbours are safe for refugees – a move that echoes controversial steps taken by Hungary in September.

“People making applications for asylum at the borders with Italy, Hungary and Slovenia would not get permission to enter Austrian territory,” an interior ministry spokesman told the Guardian. “If they make it into Austria they would be brought to registration centres, and there the authorities would start the procedure to send them back to the neighbouring countries that they came from.”

The families of asylum seekers who are already in the system will also mostly be barred from joining their relatives for three years, a development that rights groups have described as inhumane.

Austria is the latest European country to change its asylum laws in response to the refugee crisis. Denmark, Hungary, Sweden and most recently Greece have also made it harder for refugees to reach their territory.

“These measures constitute a legal wall to asylum just as despicable as a razor-wire fence,” said Judith Sunderland, acting deputy Europe and central Asia director at Human Rights Watch. “Austria should be working with other European Union countries to make sure people have a fair chance to get the protection they need, not taking unilateral decisions to pass asylum seekers around like hot potatoes.”

The Austrian interior ministry said the law would be enacted even though current migration flows are far lower than they have been for months.

Since last September, over 800,000 asylum seekers reached Austria after landing in Greece, and slightly more than 50,000 claimed asylum during that period. But since the closure of the Macedonian border in March, it has become much harder for people to move north from Greece. The average number of daily arrivals has dropped to fewer than 150, a relatively low level compared with the thousands arriving last autumn.

The level of people arriving from Italy is also relatively low, the interior ministry said, despite the start of a new smuggling season in the waters between Italy and Libya. But politicians fear a spike in arrivals later in the summer, particularly if Syrians who would previously have attempted the Greek route now travel to Libya in an attempt to reach Europe via Italy.

“For the time being, we do not have so many arrivals in Austria – there are not such high numbers from Hungary and Italy,” said the ministry spokesman. “But we have to prepared for a higher number of arrivals from Italy – and that depends on what the Italian government does.”

The move has been criticised by both the Italian government, which fears a logjam of refugees on Italian soil, and rights groups, which see the law as illegal and inhumane. Some see it as a betrayal of Austria’s history of asylum; in 1956 the country hosted hundreds of thousands of Hungarians fleeing unrest in Budapest.

Christoph Pinter, head of the UN refugee agency in Austria, said: “In the last 60 years, Austria has built up a solid asylum system and even in times of crisis has always upheld the tradition of refugee protection. Should the scheduled amendments be adopted in the current form, it would cause a renunciation of this decades-long established practice with massive consequences for refugee protection.”

Restrictions on family reunification were unfair and short-sighted, said a UNHCR spokeswoman, Ruth Schöffl. “Separation from family members does not only result in personal harm but also has negative impact on integration efforts,” she said. “UNHCR studies show that protection holders whose family members are abroad, have much more difficulties to learn the language, to find a job and to stand on their own feet.”

Italy’s prime minister, Matteo Renzi, slammed proposals to close the Brenner Pass that spans the Austrian-Italian border in the Alps. “The possibility of closing the Brenner is blatantly against European rules, as well as against history, against logic and against the future,” Renzi said in a statement.

Ban Ki-moon attacks 'increasingly restrictive' EU asylum policies