TAIPEI (AFP) - Taiwanese authorities on Sunday (June 12) refused former president Ma Ying-jeou permission to visit Hong Kong, citing national security considerations.

Ma, who stepped down on May 20 after eight years, applied to the presidential office early this month for permission to make a trip on June 15 to the semi-autonomous southern Chinese city.

He was to deliver a keynote speech at the Society of Publishers in Asia awards.

Ma, an advocate of rapprochement between Taiwan and China, was to have spoken about cross-strait relations and the Northeast Asia situation, according to his office.

But the office of new President Tsai Ing-wen, from the China-sceptic Democratic Progressive Party (DPP), rejected his application, which was reviewed by a special panel grouping senior officials from various government agencies.

"The presidential office has decided not to approve the former president's application," Tsai's spokesman Alex Huang told reporters.

Huang termed Ma's application as "sensitive", "unique" and "crucial in a national security perspective".

"The former president had been in charge of or in contact with massive amounts of top state secrets, and the plan came about less than a month since his retirement," Huang said.

"Hong Kong has been a highly sensitive area considered from Taiwan's national security point of view," he said, adding Ma must respect a state secrets law introduced in 2003.

Ma's office strongly condemned the decision, saying the purpose of the planned trip was transparent. The suggestion that secrets might be leaked "is disrespect of a retired president and has damaged the international image of Taiwan's freedom and democracy".

Ties between Taiwan and China have become frosty since Tsai won the presidential election in January, as Beijing does not trust her independence-leaning party.

China and Taiwan split in 1949 at the end of a civil war but Beijing still considers the island part of its territory awaiting reunification - by force if necessary.

Tensions eased markedly and 21 agreements between the two former bitter rivals were signed during Ma's tenure.

But public sentiment in Taiwan has recently turned against closer ties with Beijing, with voters saying trade deals have been agreed in secret and not benefited ordinary citizens.