Former Foreign Affairs Secretary Albert del Rosario on Friday was barred from entering Hong Kong airport by immigration officials, a month after ex-Ombudsman Conchita Carpio-Morales was also denied entry.

Del Rosario was supposed to attend a board meeting and shareholders' meeting in Hong Kong but upon arriving, immigration officials denied his entry and proceeded to question him.

"There had been many mundane questions that were asked and we, of course, are questioning what the reason for our being detained here and/or held up. There's been no rational explanation," Del Rosario said in a television interview over ANC.

Del Rosario arrived in Manila Friday afternoon.

Del Rosario's lawyer, Anne Marie Corominas, said told ANC they were not given any explanation by the Hong Kong immigration officers.

"He, as a former Secretary of Foreign Affairs, is travelling on a Philippine diplomatic passport. This is unlike the situation with former Ombudsman (Conchita Carpio-Morales) who was travelling on a regular Philippine passport," she said.

Corominas said Hong Kong immigration officials committed a violation of the Vienna Convention on Diplomatic Relations.

"The Chinese authorities, apparently, have checked former Secretary Del Rosario in a holding area of immigration and he hasn't been told of the reason why exactly he has been detained or asked to wait. This would seem to be a violation of the Vienna Convention," she added.

The Vienna Convention on Diplomatic Relations is an international treaty which allows members of diplomatic mission to enter a country to perform their duties and functions without intimidation by officers of the host country.

In a statement, Carpio-Morales said what happened was a "retaliatory act."

"Hong Kong's questioning of Secretary Albert del Rosario, even if he holds a diplomatic passport, confirms the detestable retaliatory act of China as it confirms that Hong Kong has shed off or been cowed into giving up its autonomy," she said.

On May 21, Carpio-Morales was barred from entering Hong Kong due to certain "immigration reasons" according to the Department of Foreign Affairs.

A month before the incident, Carpio-Morales and Del Rosario formally filed a case before the International Criminal Court against Chinese President Xi Jinping and other officials due to the "atrocious actions of Chinese officials in the South China Sea."

Justice Secretary Menardo Guevarra said he will request the Department of Foreign Affairs to know the reason behind Hong Kong official's action against the former foreign affairs secretary. Cristina Eloisa Baclig/DMS