A senior field assistant died on Wednesday after losing consciousness on the job at Tai Mo Shan Country Park.

Lam Kin-wai, 46, who worked in the Conservation Branch of the Agriculture, Fisheries and Conservation Department, injured his right palm when collecting plant specimens with his colleagues in the morning before losing consciousness.

His colleagues called the police for help, but he was pronounced dead at hospital.

Authorities said the cause of death would be investigated.

Mickey Lai, director of the AFCD, said the department would provide support and assistance to Lam's family.

"Having joined the AFCD for over 13 years, Mr Lam served the community with dedication and perseverance. His performance was excellent and he was held in high regard by colleagues," he said in a statement.

"I am deeply grieved at the loss of such a devoted colleague. On behalf of all our colleagues, I offer the deepest condolences to his family."

Civil Service chief Ingrid Yeung and the Secretary for Environment and Ecology Tse Chin-wan both expressed condolences to Lam's family.