TOKYO (REUTERS) - The Tokyo High Court has reversed a landmark ruling by a lower court that judged that the immigration authorities had used excessive force when deporting a Ghanaian visa-overstayer in 2010, leading to his death, a lawyer for the deceased's family said.

The plaintiffs are considering an appeal, the lawyer told Reuters on Tuesday (Jan 19), a day after the court handed down its ruling.

The decision comes as Japan tiptoes into a debate over whether to open its doors wider to immigration to cope with its shrinking, ageing population - a contentious topic in a society where many pride themselves on cultural and ethnic homogeneity.

Prime Minister Shinzo Abe has made raising the rock-bottom birth rate a priority and wants to focus on drawing more women and elderly into the workforce to fill gaps in the workforce rather than immigration.

In reversing the Tokyo District Court's 2014 ruling, the High Court said the force used to restrain Mr Abubakar Awudu Suraj, 45, was "not at the level to stop his breathing and was not illegal", according to the Mainichi Shimbun newspaper.

Mr Suraj, who was gagged and bound by immigration officials while on a plane prior to take-off, died of suffocation, according to a court document from the earlier ruling. The high court disputed the cause of his death, saying he died of a rare heart condition, said Mainichi Shimbun.

"The country recognised the fact that the act of restraining affected (Suraj's) condition, yet no one is held responsible,"said lawyer Koichi Kodama. "Such injustice is impermissible."

More than 5,500 people were deported from Japan in 2014, including an undisclosed number of failed asylum seekers, government data show.