MANILA, Aug 30 (Reuters) - A Manila court granted former first lady Imelda Marcos permission on Thursday to leave the country for 15 days to travel to Hong Kong and China for medical treatment and to attend a trade show.

In its ruling, the regional trial court ordered Marcos to post a 320,000 peso (US$6,870) travel bond before flying to Hong Kong on Friday and to show up at the court with her passport within five days of her return from China.

A second court was due to decide later in the day on a similar request.

"We have to get the nod from all the concerned courts," Marcos' lawyer, Robert Sison, told reporters, confident the anti-corruption court would grant her permission to travel from Aug. 31 to Sept. 14.

Sison said Marcos has an appointment on Sept. 1 with doctors at the People's Hospital of Jilin province in Changchun, China to examine her knees. She was also seeking an eye treatment at the clinic of Dr. Tong Tak Cheung in Hong Kong on Sept. 5.

In between, she was invited to attend the 3rd Jilin Northeast Asia Investment and Trade Expo, also in Changchun, Sison said.

The widow of late dictator Ferdinand Marcos faces civil and criminal cases over billions of dollars in unexplained wealth amassed during her husband's 20-year rule. She is not in detention but must get court permission to leave the country.

The 78-year-old, famous for owning 1,200 pairs of shoes and a vast collection of jewellery that the cash-strapped government was trying to auction last year, wanted to see an expert in Chinese traditional medicine.

Marcos has not left the Philippines since 2003, when she went to Europe and the United States.