The truckers strike declared earlier this week threatens to paralyze industry and leave several regions of Argentina without gas, electricity and transportation service in the middle of the Southern Hemisphere winter, Planning Minister Julio de Vido said Thursday.

"If this chaos of leaving people without supplies of fuel continues, we are going to have problems with the provision of electricity and natural gas. We are extremely concerned about the situation. This is a humanitarian problem," De Vido said in a press conference.

Several cities in Buenos Aires, Cordoba and Mendoza provinces are facing "a critical situation" because of fuel shortages, and the problems could spread to Santa Cruz and Neuquen, the planning minister said.

"We appeal to human feeling, to the need to provide gas to the cities for heating in places where it is 10 or 12 degrees below zero," De Vido said.

The government, however, will not use force to end the union's blockades of refineries and fuel depots, the planning minister said.

About 100,000 people have been affected by the gas shortages, De Vido said.

The government has decided to shift gas supplies from industry to consumers as a stopgap measure, the planning minister said.

President Cristina Fernandez's administration also plans to take legal action because the strike, which started on Tuesday, violates the hydrocarbons law, De Vido said.

The 72-hour strike spread on Wednesday to all sectors in which the union's members are employed.

Strikers blocked oil refineries in Buenos Aires, Tucuman, Santa Fe, Cordoba and Mendoza provinces.

The strike was declared by the truckers union led by Hugo Moyano, who is also the head of the General Confederation of Workers, Argentina's largest labor federation.

Moyano, a former ally of Fernandez, has been clashing with the administration and staged another strike last week.

The truckers, who plan to end the strike on Friday, are demanding pay increases of 30 percent.

Labor Minister Carlos Tomada said Thursday that he was fining the union 4 million pesos (about $887,000) for not participating in the mandatory mediation ordered by officials.

The government on Thursday filed a criminal complaint against Moyano and his son, Pablo, who are the union's leaders, for alleged "aggravated threats with the objective of obtaining measures or concessions by force from the public powers." EFE