Chief Executive John Lee said in Jakarta on Wednesday that co-operation between Hong Kong and Indonesia has reached new heights.

On the second stop of his trip to three Asean countries, the CE said he would sign 15 memorandums of understanding, covering a range of areas, during a luncheon with political and business leaders.

"First, Hong Kong's traditional strengths of trading and finance, with a collaboration between our stock exchanges and the promotion of ESG and green finance," Lee said.

"Second, commerce, logistics, maritime services and professional services, as well as third, the exchange of meteorological information to enhance disaster control, and even cooperation in aerospace technology."

Lee met Indonesian President Joko Widodo on Tuesday, with the pair discussing issues including the protection of Indonesian citizens in Hong Kong.

Asked whether the topic coming up suggests Hong Kong is not doing enough to protect Indonesian domestic helpers, Lee said it was natural for a country's leader to bring up such matters.

"I have highlighted a series of measures that protect people working in Hong Kong, whether they are local people or they are imported labour. Our law on the protection of labour applies equally to local labour and imported labour," he said.

Lee's delegation was to visit the newly built high-speed railway in Jakarta before heading to Kuala Lumpur on Thursday.