Stricter checks at immigration, including the compulsory photographing and fingerprinting of foreigners on arrival, are laid down in a revised immigration bill the Justice Ministry will present to parliament in the next few months, Isao Negishi of the ministry's Immigration Bureau said in an interview.
The revised law would allow Japan to deport any arriving foreigner it considers to be a terrorist, Negishi said.
A Japanese newspaper reported last month that a member of a radical Islamist group banned in Pakistan had entered Japan two years ago to try to establish a foothold in the country. A police report also released last month said the country was at risk of attack because of its close links with the United States.
A lawyers' group said on Jan. 11 that the country risks breaching human rights and invading individuals' privacy if it goes through with the plans.
Japan's Federation of Bar Associations said in a statement on its website that the plans should be abandoned because the fingerprinting of foreigners violated a constitutional requirement to treat people with respect.
The use of biometrics -- identifying individuals through techniques such as retinal scanning, face recognition and fingerprinting -- raises questions about privacy and control of personal information, the lawyers' group said.
"The proposal says the information will be used for criminal investigations as well," said Masashi Ichikawa, the deputy head of the committee on human rights for the lawyers' group.
"So the authorities could match footage from CCTV cameras to digitised pictures to work out exactly where an individual had been on a particular day," Ichikawa added. "We don't think that should happen to people just because they are foreign. Japanese people do bad things too."
The lawyers' group also expressed concern over the difficulty of defining "terrorism."
The Immigration Bureau's Negishi defended the constitutionality of the proposed law.
"We are aware that this information must be treated extremely carefully," he said. "But we do not consider the act of taking fingerprints a violation of the constitution in itself."
He added that the issue of whether an individual could be labelled a terrorist would likely be decided by discussion between various government agencies.
Fingerprinting and photographs were introduced at U.S. immigration checkpoints in 2004.
But the issue is a particularly sensitive one in Japan, where local governments were long required to fingerprint all resident foreigners, including "special permanent residents" of Korean and Chinese origin.
Many of these residents are descendants of those brought to Japan as forced labour before and during World War Two.
Local government fingerprinting was halted in 2000 and special permanent residents are to be excluded from the new rules.