Mr Jammeh, who came to power in a coup in 1994 aged 29, also said his government would not tolerate any terrorist or racist acts.
"I will be more dangerous in the next five years than when I was, even in uniform, because people have to change their attitude to work," he earlier said on state TV Wednesday, promising that people would see "a different Yahya Jammeh."
"You cannot be in your offices everyday doing nothing or leaving the work load on few people, and at the end of the day you expect to be paid. This has to stop. You either do your work or leave or go to jail."
"I will wipe out almost 82 per cent of those in the work force in the next five years starting this Friday (tomorrow) unless they change their attitudes," he said without elaborating.
President Jammeh, who was sworn in by chief justice Emmanuel Agim at the Independent Stadium, Bakau about seven miles from the capital, Banjul, themed his pre-inauguration address "Gambians United for the Building of Economic Super Power".
He also said that his government would not entertain the selfish pursuit of economic gain in an apparent broadside at both corrupt officials and perceived foreign enemies.
"My government will never subscribe to economic advantage from expansionist motive or suppression and domination of other nations," the Gambian leader said.