Police in the Dominican Republic have arrested more than 100 people a day before planned demonstrations.
Protesters took to the streets in the spring
Labour unionists planning the rally accused the authorities of trying to prevent them from protesting against high prices and regular power cuts.
But the police said they had arrested 106 people for carrying illegal weapons or planning subversive activities.
Once relatively prosperous, the Dominican Republic now suffers from high inflation and a banking crisis.
The strikers want the government to put a halt to rises in prices of medicine and gas, increase the minimum wage and salvage the battered electricity sector.
A union leader said the wave of arrests would not prevent the demonstration from going ahead on Tuesday.
"That won't stop the strike," Ramon Perez Figuero, president of the National Central Workers union told the Associated Press news agency.
The government has accused activists of paying people to demonstrate, a charge the unions deny.
Police said they confiscated 116 handguns and 12 shotguns, plus 6,000 tyres they say were to be set on fire to form barricades during the protest.
The government is to resume talks this week with the International Monetary Fund for a two-year $600m standby loan.
It is hoping to prop up the economy after the collapse of a major bank, Baninter, which the government has blamed on fraud.
The situation in the electricity sector is especially severe, with some areas of the Caribbean country suffering blackouts for up to 20 hours a day.
The government has not had the cash to pay subsidies to energy distributors, who in turn could not pay generators.
The Dominican peso has lost more than half its value against the dollar in the last 12 months.