"The truth is that Greece has followed a modern immigration policy, worthy of its history and culture."
But Norway, Sweden and Germany have already suspended the return of asylum-seekers to Greece and the UNHCR has said that asylum-seekers in Greece "face undue hardships in having their claims heard".
"While Greece has taken a number of steps to improve its asylum system and practice, a substantial number of asylum seekers continue to face serious challenges in accessing and enjoying effective protection in line with international and European standards," the agency said.
It noted that asylum-seekers in Greece lack basic entitlements such as legal aid and interpreters when making claims.
"Reception conditions in Greece continue to fall short of international and European standards," the UNHCR said.
Nicholas Kaminis, an activist from Amnesty International, said the situation in Greece was unacceptable.
"Greece in 2007 had an asylum approval rate of 0.04 per cent, just eight cases among 25,000 requests, and that's just unacceptably low," said Kaminis.
Interior minister Pavlopoulos said Greek authorities have difficulty in separating refugees from economic migrants because both usually arrive without identification.
The minister also highlighted Greece's "exposed geographical position".
"We are the European country closest to the Middle East and troubled regions, where our country is seen like an Eldorado," Pavlopoulos said.
"One cannot compare Greece - which is exposed by its geographical position - to Scandinavia."
Greece says its illegal migrant arrests have almost tripled in four years, from about 45,000 in 2004 to over 112,000 in 2007.
The country is fourth in asylum requests in the EU, behind Sweden, France and Britain.
It receives less refugee funding from the EU than the other three countries, Pavlopoulos said.
EU regulations say refugees must seek asylum in the country that is their first port of call in Europe.