Hong Kong authorities will conduct the last rounds of testing and finalisation of details for the National Games to be held in November, Chief Executive John Lee said on Saturday.

In a 100-day countdown ceremony, Lee said the city has held a number of test events over the past year for the upcoming sporting extravaganza and detailed the next step of preparations.

"Over the next 100 days, we will focus on streamlining the process for competitions, refining service arrangements, strengthening safety measures, and conducting final tests and rehearsals for various venues and scenarios," he said.

"That's to build a platform of fair competition for athletes and create an unforgettable experience for spectators."

For the first time, Hong Kong is co-hosting the Games, which will begin on November 9, along with Macau and Guangdong.

The chief executive was set to travel to Shenzhen in the evening to attend a separate countdown ceremony for the Games.