(3rd UPDATE) MANILA - The Philippine government blocked ex-president Gloria Arroyo from leaving the country Tuesday after she dramatically turned up at Manila airport wearing a neck brace, insisting she must face graft charges.

President Benigno Aquino's administration defied a Supreme Court ruling that Arroyo should be allowed to seek medical treatment abroad immediately for what the 64-year-old has said is a life-threatening bone disease.

At the end of a tension-filled day of Philippine politics, Arroyo arrived at Manila airport in an ambulance and was escorted into the building in a wheelchair wearing a neck brace, with the events broadcast on television.

Justice Secretary Leila de Lima said immigration authorities had been told to stop Arroyo from leaving the country, prompting outrage from the ex-president's camp.

"We have rights enshrined under the constitution, we will fight for our rights," Arroyo's spokeswoman Elena Bautista Horn told ABS-CBN television from inside Manila airport as they sought to negotiate with airport officials.

SC okays travel abroad

The Supreme Court had earlier in the day overturned a government ban imposed last week barring Arroyo from travelling abroad.

A spokesman for the Supreme Court said the justices had ruled 8-5 that the ban, which also applied to her husband, was unconstitutional because they had not yet been charged with any crime.

"They (Arroyo's lawyers) were able to show... the (travel ban) would probably work (as) an injustice against them," spokesman Midas Marquez said.

"This was of course consistent with the constitutional presumption of innocence."

However de Lima insisted that the travel ban would remain in place until the government formally received the Supreme Court's decision.

She said government lawyers would file a motion for reconsideration of the court order and expressed hope that they might convince the court to change its mind in a hearing next week.

Contempt charges

In an escalating showdown between the branches of government, Marquez then responded to de Lima's comments by issuing a statement insisting the court's order was effective immediately.

"Since they (the Arroyos) have complied with our conditions, they are free to exercise their constitutional right to travel," he said, warning de Lima may face contempt of court charges.

Arroyo remained inside Manila airport late into the evening on Tuesday, but eventually left after it was clear she would not be allowed to leave the country, according to an AFP photographer on the scene.

Arroyo, who was president from 2001 to 2010, faced wide-ranging allegations of corruption and vote-rigging while she was in power.

Bringing Arroyo to justice

Aquino, who won presidential elections by a landslide last year on a strong anti-corruption platform, has vowed repeatedly to bring Arroyo to justice and said he wants her to be formally charged before Christmas.

As the deadline for charges loomed, Arroyo said last week she needed to urgently receive medical treatment overseas for what she said was a rare bone disease, following three unsuccessful spine operations in Manila this year.

But Aquino and de Lima said last week that Arroyo could receive adequate medical care at home and they suspected she might be seeking to flee to a country that had no extradition treaty with the Philippines.

Aquino has faced repeated setbacks in his high-profile campaign to bring Arroyo to justice.

In one of the most significant blows, the Supreme Court ruled in December last year that a "truth commission" Aquino set up specifically to investigate Arroyo was unconstitutional.

Arroyo has retained political influence since stepping down as president, partly by winning a seat in the House of Representatives in last year's elections.

Aquino has also accused her of placing allies in positions of power before she stepped down, including justices in the Supreme Court.