The Leisure and Cultural Services Department has apologised for the mismanagement of Sunday's mass tai chi show to celebrate the handover that resulted in dozens of people being treated for heatstroke.
The 'Mega Tai Chi Show' at the old Kai Tak airport site attracted 20,236 participants despite the 31degree heat.
Twenty-nine people were treated for heatstroke and two were sent to hospital.
'We will learn from this experience and do better when holding such large-scale events in the future,' department assistant director (Leisure Services) Olivia Chan Yeuk-oi said on a radio show yesterday.
'We apologise to the citizens affected and, most importantly, we hope the two participants in hospital will recover very soon.'
A 61-year-old woman remained in stable condition at Queen Elizabeth Hospital yesterday, and a 76-year-old man was in satisfactory condition in Kwong Wah Hospital.
Department representatives visited the two patients yesterday to convey the regards of Chief Executive Donald Tsang Yam-kuen, Permanent Secretary for Home Affairs Carrie Yau Tsang Ka-lai and the department's director Thomas Chow Tat-ming.
Participants were asked to arrive for Sunday's event at 8am and waited until 10.30am to practise tai chi together for 20 minutes.
The Observatory said the temperature was 31 degrees at its Tsim Sha Tsui station at 11am.
Ms Chan said they had planned to drive people home by bush from 11.45am to 1pm, but the last bus did not depart until 1.20pm.
The delay may have occurred because it took longer to load people on the buses, she said.
'We will make a better crowd dispersal arrangement when holding similar activities,' Ms Chan said.
Many participants told the phone-in programme that they were given only one to two bottles of 700ml water, which was not enough in the sweltering heat.
Ms Chan said they had arranged for about 60,000 bottles and planned to give each participant a bottle when they arrived and another one when they left.