The metal door to the office was blown off in the explosion
and a hole ripped in the wall. Shattered glass and broken furniture were strewn around.
Firefighters extinguished the flames from the explosion, which knocked out electricity in the eight-storey building.
Raham Abdel Karim, an Al-Arabiya office manager, said death threats had recently been made against staff and the government had been informed of them.
She said: "We received a clear threat they would explode the office and kill some employees."
An official at the station said anonymous callers had last week threatened to harm employees and burn the office after the station had aired a tape of Ismail Haniyeh, the Palestinian prime minister of the governing Hamas group, Reuters news agency reported.
Witnesses said Al-Arabiya employees had not arrived at work for several days.
Hamas said the broadcast of Haniyeh's comments had taken his words out of context and vowed to pursue legal action against the station if it did not apologise to Haniyeh.
Officials from Al-Arabiya said the channel had shown an unedited recording that was taken from a Palestinian Web site.
They also allowed an adviser to Haniyeh to go on the air to explain the group's position on the tape.
Ismail Rudwan, a Hamas spokesman, said the group was not involved in the attack nor in making any telephone threats.
Ghazi Hamad, a Hamas spokesman, said: "Despite the disagreement between us and Al-Arabiya, we reject this method and we consider it unacceptable. I have urged the interior minister to find out who is responsible."
Mahmoud Abbas, the Palestinian president and leader of Fatah, also condemned the bombing, the Palestinian news agency WAFA said.
Hamas and Fatah have clashed violently in recent months, with agreement between the parties about a unity government not yet reached.
Joel Campagna, the Middle East programme co-ordinator for the Committee to Protect Journalists, said: "We condemn this shameless attack and call on the Palestinian Authority to locate those responsible for this crime and bring them to justice.
"The rising climate of intimidation against journalists has substantially eroded press freedom in the West Bank and Gaza."