Manila: The Philippine government on Tuesday rejected an appeal from former President Gloria Arroyo to travel abroad for medical treatment, saying she may be trying to avoid a graft probe.

Arroyo, 64, had asked the government to allow her to head overseas for expert help on what she said was a rare bone disease, after unsuccessful operations on her spine in Manila this year.

But Justice Secretary Leila de Lima said Arroyo could be adequately treated in the Philippines and that there were concerns she might not return if she was eventually charged with graft.

"We see no immediate necessity for her to leave and therefore, affect the progress of ongoing preliminary (corruption) investigation proceedings," de Lima told reporters.

Arroyo's lawyer, Raul Lambino said in an interview with DZMM radio that de Lima's decision "is purely tyrannical".

Arroyo had requested to go to Singapore, Germany and several other countries to seek medical treatment.

De Lima said she was suspicious that many of the countries Arroyo wanted to visit had no extradition treaty with the Philippines.

"I can't avoid being concerned that five of these countries have no existing extradition treaties with us, and there lies the risk, something I can't afford to take," she said.

Arroyo, who was president from 2001 to 2010, has been accused of massive corruption and of rigging the 2004 election to ensure a narrow victory over actor-turned-politician Fernando Poe.

She was required by constitutional term limits to stand down last year, but nevertheless retained political influence by running for, and winning, a seat in the House of Representatives.

Arroyo's successor as president Benigno Aquino, has launched multiple investigations into her alleged misdeeds and told reporters last month she would soon be charged with corruption.

Before Tuesday's ruling, Arroyo was on a travel "watch list", meaning she had to ask permission before travelling abroad.