JAKARTA (DPA) - Indonesian presidential candidate Prabowo Subianto faltered during a televised debate ahead of upcoming elections when his opponent, incumbent President Joko Widodo, used tech jargon in a question.

Mr Joko asked Mr Prabowo what he would do to support unicorns, a term for start-up companies valued at over US$1 billion (S$1.35 billion), in the second presidential debate on Sunday (Feb 17) night.

"What do you mean by unicorns? Those online things?" Mr Prabowo, a United States-educated former general, asked before engaging in nationalist rhetoric about capital flight.

"If we're not careful, the enthusiasm for Internet things, e-commerce and other e-things, will speed up the flight of domestic money to other countries," he said.

Sunday's debate focused on infrastructure, the environment and natural resources, but neither candidate talked about climate change.

The April 17 presidential election is a repeat of the 2014 vote, when Mr Joko narrowly defeated Mr Prabowo after a divisive campaign period.

During the debate, Mr Joko touted his government's success in overcoming forest fires, which produce smog that often affects neighbouring countries Singapore, Malaysia and Thailand.

"We don't want forest fires to happen again," he said.

"Over the past three years, there have been no forest and peat fires," he said.

But environmental campaigning organisation Greenpeace disputed the president's claim.

"The fact is since the tragic forest fires of 2015, forest and agricultural fires have happened every year," Greepeance said on Twitter.