Austria has announced it is ready to use soldiers and tanks to stop migrants crossing its border with Italy, as Brussels urged Europe to help Italian authorities manage an “unprecedented” arrival of people from north Africa.

Austrian defence minister Hans Peter Doskozil announced that four Pandur armoured personnel carriers had been sent to the Tyrol region and 750 troops were on standby.

Speaking to the Kronen Zeitung, Doskozil said troops on the Brenner pass would be “indispensable” if large numbers of people continued to arrive in Italy from the central Mediterranean. He told the popular daily newspaper that border controls on the busy Alpine pass would be reintroduced very soon, although his office said no timetable for the measures was fixed.

Austria and Italy are both part of the EU’s border-free Schengen zone, which eliminates passport checks at the frontier. Many countries reintroduced some border controls after 1 million refugees and migrants arrived in Europe in 2015.

Migration is a highly charged topic in Austria and Italy, which both face elections in the next 12 months.

A record number of people are expected to cross the Mediterranean sea in 2017, with arrivals 20% higher than this time last year. Since January, 85,183 people have arrived in Italy, compared with 71,279 last year, according to the latest data from the International Organization for Migration. A total of 2,150 are reported to have drowned in the central Mediterranean this year.

Franz Kompatscher, the mayor of Brenner, said the town had not yet seen troops, but fears had risen after a large number of arrivals in southern Italy, in the run-up to snap elections in October.

“There isn’t a problem with migrants here, it’s not like it was last year,” Kompatscher said. “Very few come here now because they know it’s very difficult to cross the border. Some do manage to cross, but it’s not easy.

“But again, people are also worried because they see that politicians aren’t doing anything to control this situation.”

Frans Timmermans, a European commission vice-president, said Italy’s call for solidarity was completely justified and urged other EU member states to meet their promises of housing refugees in Italy under an EU relocation scheme. “It would make a world of difference if member states would just do what they agreed before.”

He was clear that Brexit did not exempt the UK from taking part in a new refugee relocation scheme, as the commission announced a plan to bring asylum seekers from Libya, Egypt, Ethiopia and Sudan to Europe. “This is an exercise we need to do at a European level and I count on solidarity from all member states including the United Kingdom.”

Details of the plan remain sketchy, but the idea is similar to a scheme for Syrian refugees in Turkey. European countries have taken in 16,500 Syrian asylum seekers from Turkey, an initiative the UK supported. A parallel scheme to relocate refugees from camps in Italy and Greece has lagged far behind a 160,000 target, as some central European countries have refused to take part.

The EU executive also gave its backing to plans for a controversial code of conduct to govern NGOs that rescue migrants at sea. Italy wants to subject NGOs that undertake search and rescue operations in the central Mediterranean to the control of Italian and Libyan coastguards.

On Tuesday, the EU executive endorsed the general idea of a code of conduct, while calling on the Italian authorities to work with NGOs to draw it up. But UN agencies gave the plans a withering response, while accusing Nato and commercial shippers of ignoring the duty of rescuing people at sea.

“Quite often we see shipping companies switching off their GPS system … in order not to rescue people. This is also happening on a daily basis in the Mediterranean sea,” said Vincent Cochetel, the head of the UNHCR’s Europe office.

In unusually pointed language, he turned the spotlight on Nato frigates in the Mediterranean, namely Operation Sea Guardian, a plan to boost security on the seas and combat terrorism.

“Can you tell me how many ships operating under Nato Operation Sea Guardian, have been rescuing people at sea from the central Mediterranean over the last two or three years? Has that happened? Can we have a code of conduct for military ships cruising through the central Mediterranean?”

Eugenio Ambrosi, the director of the Europe office of the International Organization for Migration in Europe, said Europe was on “a very slippery slope” with the proposed code of conduct. “What is the problem with NGOs? I was asking myself the same question. I don’t know … I know that they are saving lives and I know that that is an imperative.

“Member states also have a code of conduct – it is called European law, including the duty and obligation to show solidarity in fact and not in words.”

He said the EU was too fixated on arrival numbers and was neglecting why people made the journey and the plight of 240,188 internally displaced people in Libya, forced to leave their homes after the country collapsed into civil war.

Migration is one of the most divisive issues for the EU, with countries deadlocked over how to reform the bloc’s asylum rules. Meanwhile member states along the EU’s Mediterranean border have accused some northern neighbours of not doing enough to help in the immediate crisis. Some EU officials counter that Italy and Greece have not done enough themselves in the past, pointing to slow procedures to deal with refugees and migrants.

The latest Brussels plan calls for Italy to open more detention centres and increase the number of people returned to their country of origin if they fail to qualify for asylum. The measures will be discussed by EU home affairs ministers in Tallinn on Thursday.