(LJUBLJANA) - The Slovenian parliament late on Friday approved legislation toughening conditions for asylum seekers to curb the flow of migrants and avoid the country becoming a bottleneck on the so-called Balkan route.

"The aim of this bill is to enable fast and efficient asylum procedures for those that really need asylum... and to give grounds for an efficient policy of returning those that do not meet the conditions for international protection," Interior Minister Vesna Gyorkos Znidar said when presenting the bill.

The International Protection bill was approved by 45 votes to 4 in the 90-seat parliament.

The opposition centre-right parties boycotted the vote after their requests for tougher asylum restrictions and for a cap on migrant numbers were rejected by the centre-left three-party coalition.

The new bill simplifies the rejection procedure for asylum seekers from so-called safe countries, shortens the deadline for an appeal and reduces the financial assistance for refugees and their families in case of a reunification.

Human rights group Amnesty International criticised the proposed asylum legislation saying it significantly reduced refugees and asylum seekers' rights and was at some points in violation of the European Convention on Human Rights.

With its northern neighbour Austria restricting entries since last month and over 30,000 migrants in Greece waiting to head for the north, Slovenia fears becoming a bottleneck on this migrant path.

Almost half a million migrants heading for Austria and Germany have crossed Slovenia since October 2015 following Hungary's decision to seal its borders for refugees.

During that time, only 442 migrants have applied for asylum in the tiny Alpine state of two-million that controls 670 kilometres (417 miles) of the passport-free Schengen area's external border with Croatia.