ATHENS, Greece -- Greek authorities need to "wake up" and do more to adequately accommodate a burgeoning number of refugee arrivals that has become a full-blown humanitarian emergency requiring a natural disaster-like response, a senior official with the UN refugee agency said Friday.

UNHCR Europe Bureau Director Vincent Cochetel said more than 109,000 people have arrived in Greece since the beginning of the year, most of them Syrians and Afghans fleeing war and violence in their homelands. Most aim to relocate to other European countries.

He said some Greek islands receive up to 1,000 arrivals each day from neighbouring Turkey. But neither national nor local authorities have mobilized to the degree needed to effectively deal with the influx.

"We just want to have some people in charge and co-ordinating, that's what we need," Cochetel told a news conference. "We need to step up the emergency response again as if it was a natural disaster."

He said Greek officials must "get serious" about building more centres to provide shelter, food and other services to meet people's basic needs.

Cochetel said the UNCHR is aware of Greece's acute financial crisis, but still noted that the country hasn't increased its 1,100-person refugee housing capacity in six years.

The official described facilities for refugees and other migrants on all Greek islands as "bad," accusing local authorities of shirking responsibility to provide them with the essentials.

Cochetel said on the island of Kos, authorities haven't stepped up to provide electricity and running water to one empty building that could be turned into a housing site.

He added that he is not convinced that Greek authorities are incapable of finding adequate accommodations for about 500 Afghans now living in a park in central Athens.

"There are so many empty buildings in this country, so much land not cultivated," Cochetel said. "Don't tell me it's impossible to find a site for those people."

The official said the EU needs to show more solidarity with Greece. Plans to relocate as many as 16,000 refugees from Greece to other European nations is "a step in the right direction, but clearly insufficient" in light of the huge increase in arrivals, he said.

The UNHCR and other humanitarian organizations are ready to assist Greece in coping with the huge numbers of refugees, but the government needs to take action and show that it's living up to its responsibilities, Cochetel said.

"We're not going to take the responsibility of the Greek authorities to manage reception centres, to manage arrivals," he said.

Speaking earlier in parliament, Greek Prime Minister Alexis Tsipras defended his government's track record in dealing with the crisis in the six months it has been in power.

He said his government is moving ahead with creating reception areas on the mainland and on the islands, including on Kos, and is in the process of finding adequate accommodations for the Afghans living in the Athens park.

Tsipras stressed his government would never "leave people around us to perish from hunger or the cold," but urged other EU nations to assume their share of the refugee burden.

"You can't talk about a European Union, about common borders and solidarity," he said, "when the only thing that you care about is not letting these people come from countries who have become repositories of human souls."