Many of Portugal's public services have ground to a halt as workers strike in a bid to weaken the government's resolve to make deep budget cuts.
Rail services, urban transport, flights, rubbish collection, healthcare and banking were all disrupted by the first general strike in decades.
The action was largely peaceful but two women were injured on a picket line.
Parliament is set to vote on a budget meant to tackle the mounting debt crisis on Friday.
The Socialist government wants to quell international unease over the country's public spending and deficit by cutting wages for public sector workers, freezing pensions and increasing taxes.
With the main opposition party saying it will not block the budget, analysts expect it to have an easy passage through parliament.
While the strike is unlikely to throw the government off course, it may fuel fresh concern on the markets, especially following the government's revelation this week that Portugal's budget deficit actually grew this year instead of shrinking, the BBC's Sarah Rainsford reports from Lisbon.
The country's main unions, the UGT and CGTP, hope the 24-hour action will be the most effective in two decades
- Nearly 80% of trains were not running, and bus and ferry links in Lisbon were disrupted, along with the metro service
- Both air traffic controllers and airport ground handling operators were on strike, meaning dozens of flights in and out of Lisbon had to be cancelled or rescheduled
- All of the country's ports were closed, according to the unions
- Fewer than 10% of the workforce at Volkswagen's Autoeuropa plant near Lisburn turned up for work, according to unions
Police in the northern town of Calendario arrested the manager of a hypermarket who allegedly drove his car into a picket line, injuring two women and threatening others.
A union official said one of the women had had her leg crushed by the car.
Police said they had arrested the man for dangerous driving and possession of a weapon.
Roads in and around the capital were choked with heavy traffic as many people chose to commute by car but in the city centre traffic was normal, Reuters news agency reported.
Cafes and shops were open and vans delivered goods as usual, it said.
In contrast to the recent protests against pension reform in France, the Portuguese strikers have not planned mass demonstrations but are confining themselves to pickets.
One CGTP leader, Manuel Carvalho da Silva, said there was strong public support for the strike as it expressed "outrage at injustices".
Another trade unionist in Lisbon told AFP news agency it was unacceptable that workers should "make all the sacrifices".
"We cannot accept that the first, second and third priority of Portugal is the deficit," said Joao Proenca.
But employees interviewed by Reuters said that, while they sympathised with the strikers' grievances, the action would only bring inconvenience and no resolution.
"It won't solve anything, it's just a way of demonstrating," said one.
Struggle to compete
The opposition Social Democrats have said that, in order to not jeopardise the country's fragile finances, they will abstain from the vote on Friday rather than vote against the measures.
Lisbon is trying to convince international investors that Portugal will not be forced to seek a bail-out like Ireland or Greece.
The budget aims to reduce Portugal's deficit from 7.3% to 4.6% of GDP in 2011.
Portugal has failed to prosper or drive up productivity since joining the euro at what many now say was an unrealistic exchange rate, BBC Europe business correspondent Nigel Cassidy says.
The country found it especially difficult to compete with China in a previously strong sector, the manufacturing of textiles and shoes.
With 80% of its public debt held abroad, Portugal now finds itself at the mercy of bond traders and wants to convince the markets that it will be able to meet its commitments, our correspondent says.