The US is considering imposing oil sanctions against crisis-plagued Venezuela as it looks to put pressure on President Nicolas Maduro's government "to return to the constitution".

Secretary of State Rex Tillerson, who is on a South American tour, told reporters in Argentina's capital Buenos Aires the US could prohibit Venezuelan oil imports and restrict exports of oil or US-refined products to Caracas.

"One of the aspects of considering sanctioning oil is what effect will it have on the Venezuelan people?" Tillerson said at joint press conference with Argentine Foreign Minister Jorge Faurie on Sunday.

"Is it a step that might bring this to an end, to a more rapid end? Because not doing anything, to not bring this to an end is also asking the Venezuelan people to suffer for a much longer time," he added.

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The US blames the Venezuelan president for the economic and political crises that have led to violent protests, and shortages of food and medicine.

Maduro has accused the US and its allies of trying to undermine his socialist government.

The Venezuelan leader, who has been in power since 2013, is seeking another term in office after the pro-government Constituent Assembly called for snap elections by the end of April.

Inflation in Venezuela could spiral to 13,000 percent this year, according to the IMF.

The economic crisis has forced thousands to cross the border to neighbouring countries.