The government has repatriated 22 illegal immigrants from Bangladesh in the fourth round of its contentious mass deportation program using a state-chartered plane, the Justice Ministry announced Thursday.

Subject to the repatriation, conducted Wednesday, were visa overstayers and other illegal immigrants who had long "stubbornly" ignored deportation orders issued by the state, immigration official Atsushi Gokan of the Justice Ministry said.

All deportees were adult males aged 23 to 53, with none handcuffed while aboard out of consideration for their human rights, Gokan said.

The government move Wednesday marked the fourth time it has flown back illegal immigrants en masse using a specially chartered plane, following Filipinos and Thais in 2013 and Sri Lankans and Vietnamese in 2014.

The program, introduced in 2013, is considered cheaper than when the state repatriates immigrants one by one. The Justice Ministry also touts the program as safer in that it involves no commercial passengers on board.

In a revelation that could spark ire among human rights activists, the ministry acknowledged some of those deported Wednesday had applied for refugee status, albeit unsuccessfully.

Some of these failed applicants, Gokan admitted, were repatriated within the first six months after the final rejection — a period in which they are legally allowed to file a lawsuit against the state in a bid to nullify the ministry's decision.

The government similarly deprived some Sri Lankans it deported in December 2014 of the last-resort shot at refugee status — a decision decried by critics as life-threatening because it could expose them to persecution back home.

On Thursday, immigration officials reiterated that the decision to deport such unsuccessful applicants presented no human rights violation, because they officially lost asylum-seeker status the moment they were deemed ineligible for Japan's refugee recognition criteria, which itself is often criticized for being overly conservative.