A Palestinian human rights group says the Gazan man arrested and put in detention by Israel is suffering from psychological problems in custody.

The Gaza-based Palestinian Center for Human Rights says one of its lawyers was permitted to visit Dirar Abu Sisi, an engineer at Gaza's central power plant, on Sunday. He told the group he was denied access to a lawyer for 25 days.

Open gallery view Veronika, wife of Dirar Abu Sisi, holds up her husband's picture at the Islamic Centre in Kiev in this March 11, 2011 file photograph. Credit: Reuters

According to foreign reports, Abu Sisi was abducted by Israeli security forces after boarding a train in the eastern Ukraine city of Kharkiv last month. Abu Sisi, whose wife is Ukrainian, was in the country applying for citizenship.

Abu Sisi told the attorney for the human rights group that he was forcibly removed from his train compartment and brought handcuffed and hooded to an apartment. He said at least six Israeli agents interrogated him before flying him to Israel.

Israel confirmed on Sunday that it was holding Abu Sisi but much of the remaining information surrounding the case remain under a gag order.

Abu Sisi's wife, Veronika hired attorney Smadar Ben-Natan to replace the public defender who had been assigned to represent her husband.

Ben-Natan told Haaretz that she met with her client in prison and that while he is in satisfactory physical condition, he does have a history of medical problems. She was unable to discuss the arrest or the investigation due to the gag order.

At the request of the Shin Bet security service and the State Prosecutor's Office, a comprehensive gag order was issued at the time of Abu Sisi's arrest, around a month ago. About 10 days ago the order was modified to permit the publication in Israel of details already reported in the foreign media.

Some foreign reports cite sources in Gaza as saying that Abu Sisi had ties to Hamas and supported the organization, while others say he was never politically active.

A number of the reports imply that the Ukrainian authorities knew about and cooperated with Abu Sisi's alleged abduction and transfer to Israel by Israeli intelligence agents.

During a visit to Israel last week, Ukrainian Prime Minister Mykola Azarov evaded reporters' questions about the affair, saying only that it was under investigation.