Some 3,000 Zambian trade unionists have marched to parliament as a national strike takes hold.
This is the first major backlash against IMF-inspired reforms
The BBC's Penny Dale in Lusaka says this is one of biggest stayaways in recent years.
Under pressure from donors, income tax was increased and public sector wages frozen in this year's budget, which the unionists are urging MPs to reject.
The government had vowed to crush any protest but the police later said the march could go ahead.
"We have granted them a police permit but we will not tolerate breach of the law or disorderly behaviour," Lusaka Police Chief Chendela Musonda told journalists.
Our correspondent says many protesters wore black headscarves as a sign of mourning.
She says post offices and banks are shut but most shops are open.
The strike is the first major backlash against stringent economic policies imposed to satisfy donors.
Unions leaders threatened to hold another strike if the government refused to back down.
"The government will certainly feel the impact of this strike action and we plan a three-day strike and demonstration if they will not reduce tax and remove the wage freeze," Zambia National Union of Teachers head Roy Mwaba said.
Union leaders say wage freezes were made illegal in 1998.
Meanwhile, President Levy Mwanawasa has sent ministers to the provinces to explain why the government had
raised taxes and frozen wages, state radio reports.
The government increased personal income tax from 30-40% and imposed a wage freeze
on civil servants two weeks ago.
They are aiming to keep the wage bill within 8.1% of GDP as agreed with the International Monetary Fund.
The IMF froze lending to Zambia
last year after its deficit widened to 3% from an initial forecast of 1.55%.
Workers argue that the government should cut back on "lavish" spending on things such as presidential trips rather than increases taxes.