Measures including deporting failed applicants, curbs on repeat applications and pre-screening of new asylum seekers are being considered as part of changes to the country's immigration system, an official said on Wednesday.
If implemented, the changes would make Japan an even harder-to-reach destination, activists say. The country is already one of the developed world's least welcoming countries for refugees, accepting 11 of a record 5,000 asylum seekers in 2014.
"We're not looking to increase or decrease the number of refugees coming to Japan, but to ensure real refugees are assessed quickly," said Hiroaki Sato, a Ministry of Justice official overseeing the proposals. He could not say when changes would be finalised.
On Wednesday, around 100 foreigners on "provisional release" from immigration detention - many of them asylum seekers - marched through Tokyo's government district in the driving rain, calling for refugee visas.
"The system is so difficult already," said Ali Jafari, an 54-year-old Iranian who said he came to Japan as a political refugee. "To make it tighter is just cruel."
The UNHCR said on Tuesday it expects at least 850,000 people to head to Europe this year, many of them refugees from Syria's four-year civil war. The scale of the crisis has promoted the European Union to move towards quotas for acceptance of asylum seekers.
But Japan's government does not see escaping war as a legitimate reason for claiming asylum, and has no plans to widen its criteria to include flight from conflict, said Sato.
The strict interpretation of refugee law and the country's geographical and cultural distance from the Middle East deter Syrians from seeking asylum in Japan, refugee policy experts say. Only 63 have applied for asylum in Japan since 2011, according to government data.
Tokyo gave $167 million to the UNHCR in the first half of this year, making it the second largest government donor. But by tightening its national refugee system Japan risks shirking its global duties, say activists.
"As a developed country, there's a responsibility to protect these people," Mitsuru Miyasako, head of rights group Provisional Release Association in Japan, told Reuters at the Tokyo demonstration.