Former Justice Minister Masahiko Komura criticized the government Wednesday over Friday's deportation of a man believed to be the eldest son of North Korean leader Kim Jong Il.
"Not all Japanese people are really satisfied with the deportation," Komura, also a former foreign minister, told a meeting of his Liberal Democratic Party faction.
He said those in charge of diplomacy should explain how the decision was made, noting that investigators could have legally detained the man.
The man believed to be Kim Jong Nam, 29, and three companions -- two women and a young boy -- were deported from Japan to China on Friday after being detained May 1 at Narita airport, Chiba Prefecture, by immigration authorities for using forged passports.
Entry stamps in the man's passport showed it had been used to enter Japan three times previously. But the government was unable to confirm whether it was the man in question who had used the passport on those occasions.
Following the incident, the government said Monday it will toughen immigration controls.