Strikes by aviation, maritime and public transport workers has effectively cut off Papua New Guinea.
A groundswell of political unrest in recent weeks culminated in the general strike on Thursday ahead of a no-confidence vote on Friday against Prime Minister Peter O'Neill, who has refused to resign over corruption allegations.
Last month, weeks of peaceful protests by university students ended in violent clashes with police in which officials said nearly 40 people were injured, including four who were shot.
Although the strike in the three main urban centres of Port Moresby, Lae and Mount Hagen involves more than one industry, it is the aviation strike that is having the greatest impact, said Martyn Namorong, head of the PNG Resource Governance Coalition.
Poor roads through the thickly forested highlands that separate its few large cities mean that travellers are effectively stranded without air travel, Namorong told Reuters.
"For those who are travelling it's a major impact on people about to commute throughout our country because our country is severely dependant on air transport," he said by phone from Port Moresby.
Human Rights lawyer Moses Murray, a spokesman for the strikers, told Radio New Zealand that the action was peaceful and focused on the aviation, maritime, public transport and banking sectors.
O'Neill came to power in 2011 promising to rein in corruption but is facing allegations he authorised millions of dollars in fraudulent payments to a leading law firm.
In 2014, an anti-corruption watchdog issued an order for his arrest over the incident, which O'Neill denies. He refused to submit to the warrant and ordered the watchdog stripped of its funding.
The strikes have contributed to a growing sense of unease in Port Moresby ahead of the no-confidence vote, said Noel Anjo, a leader of the student protests.
