HONG KONG - Beijing should inform Hong Kong "as soon as possible" when it detains Hong Kongers and improve the notification mechanism to the standards of the city's arrangements with foreign countries, Chief Executive Leung Chun Ying said in an interview with South China Morning Post.

"The starting point, and to me it's basic and fundamental, is that we want to know as soon as possible when a Hong Kong resident is arrested by a jurisdiction outside of Hong Kong," Mr Leung said in the interview with SCMP published on Tuesday (June 28).

"That applies to foreign governments and should also apply to the mainland, because we are two systems."

Mr Leung was speaking in the wake of explosive revelations by a Hong Kong bookseller who said he was detained for eight months on the mainland without access to his family or a lawyer, allegedly for selling books banned by Chinese authorities.

Mr Lam Wing Kee was one of five employees of a Hong Kong company - which published salacious books about leading Chinese politicians including President Xi Jinping - to go mysteriously missing last year. One of them, Lee Bo, was said to have been abducted in Hong Kong. All have since re-emerged on the mainland.

Beijing-backed Mr Leung, who has been accused of dragging his feet over the case, announced last week he had written to Beijing relaying Hong Kongers' growing concerns that their freedoms - guaranteed under Beijing's 'one China, two systems' pledge - are disappearing.

Mr Leung said he had received a reply from Beijing "to start discussion on the existing notification mechanism between the two places". He did not rule out the possibility of personally going to Beijing to take up the matter.

Mr Leung also gave his strongest hint yet that he would seek a second term in elections due to be held in 2017.

He stressed the importance of experience and shrugged off talk of a looming "Anyone but CY" campaign by his opponents, SCMP reported .

The timing suggests he will wait for the Sept 4 Legislative Council election results to gauge public sentiment. If the pro-establishment camp receives a drubbing, it will be seen as a proxy of voters rejecting the status quo and, with that, Mr Leung's re-election chances may also be in jeopardy, said SCMP.

"Five years ago, back in June 2011, I had not made up my mind. So now in June 2016, I have not made up my mind. There's still plenty of time," Mr Leung was quoted as saying.

"I have enjoyed my work every day in the past four years, despite the challenges. I enjoy seeing ­results. People may not talk about the positive results, the accomplishments every day, but you know they are out there."