Masoud Sedaghatzadeh, arrested at Kuala Lumpur's international airport on February 15, is among three Iranians being held over incidents in Bangkok that saw Tehran accused of a terror campaign against Israel -- which it denied.
The alleged plot emerged after an apparently unintended explosion at a house in the Thai capital. Two suspects are in custody in Thailand, including one who hurled a bomb at police while fleeing, blowing off his own legs.
At a criminal sessions court in Kuala Lumpur, Judge S. Komathy described Sedaghatzadeh, 31, as a "fugitive criminal" and said she disagreed with defence arguments that there was no evidence against him.
"In my view the conduct of the respondent is inconsistent with that of an innocent man," she said.
"The prosecution has shown that the respondent is a fugitive criminal... as he is wanted by the Thai police for offences which come within the definition of extradition offences.
"I'm allowing the application for extradition and the respondent is to be detained in prison pending an order from the minister (of home affairs)."
Sedaghatzadeh, who was handcuffed and wore a striped polo shirt, told the hearing through an interpreter that he would appeal to the high court against the extradition.
"I require more time to defend myself," he said.
The explosions in Thailand followed bomb attacks targeting Israeli embassy staff in India and Georgia the previous day, pushing tensions between arch-foes Iran and Israel to a new spike.
Thai police have said that Israeli diplomats were the intended target of the plot, and that prosecutors have referred a case against five Iranian suspects to court for a possible trial.
Aside from Sedaghatzadeh and the two being held in Thailand, two other suspects are believed to have returned to Iran.
Sedaghatzadeh was looking to travel on to Iran himself when he was arrested, Malaysian authorities have said.
He has said he is a car parts dealer who came to Malaysia on business, while his lawyer Mohamad Nashir Hussin said his client had visited Thailand for a "short holiday" and was not involved in the house explosion.
"There is no evidence of direct involvement and of knowledge (of the explosives) from the respondent," he told the court Monday.
Prosecutor Kamal Baharin Omar said closed circuit television footage from cameras in the area showed Sedaghatzadeh and two other suspects leaving the house after the blast.
He added that if extradited to Thailand, Sedaghatzadeh faced charges of using explosives -- which carries a maximum penalty of life imprisonment -- and causing harm with explosives.