Heavy security was put on the streets during the march
Angry Nigerians have taken to the streets of the commercial capital Lagos to protest at what they say is the poor performance of the government.
Thousands walked to the government house in Ikeja to protest against rising fuel prices, low minimum wages and the slow electoral reform.
Armoured cars were stationed on the route to guard against unrest.
The Nigeria Labour Congress (NLC) is planning a further protest on Friday in the southern oil-producing Niger Delta.
The government said the protests may be used "to cause chaos", and urged the NLC to return to negotiations.
Heavy security was put on the streets during the march.
The BBC's Fidelis Mbah in Lagos said the march grew as they picked up more people on the way.
"Commercial drivers, and motorcycle taxi operators are leaving their work and joining the protest," he said.
At every corner there are armed police, and at least four armoured cars followed the demonstration, our correspondent says.
The NLC says further protests are planned for the southern Delta State and cities in the north over the next 10 days, before a second phase of demonstration throughout the country.
"We are determined to carry these protests to all nooks and crannies of the country," said NLC president Abdulwaheed Omar. "We are not afraid of the government."
The NLC wants the government to scrap its plans aimed at deregulating the oil sector, saying the move would lead to further fuel shortages and push up pump prices.
Nigeria imports some 85% of its oil petroleum product needs, despite being Africa's largest oil producer.
The NLC is also demanding higher minimum wages, currently about $38 (£25) per month, and electoral reforms to avoid a repeat of what it calls flawed polls in the past.