South America's Mercosur trade bloc members are supposed to help each other's economies grow.
Instead, Paraguay says Argentina is trying to overcharge for the use of its power lines to deliver Paraguayan electricity to Uruguay.
Paraguay has broken off talks with its larger neighbor, saying $48 per megawatt hour to deliver electricity from a hydroelectric dam is nearly five times what Brazil charges for the same thing.
Deputy Mines and Energy Minister Mercedes Canese said Monday that Paraguay's foreign minister will now see if this price comes straight from Argentine President Cristina Fernandez, or some low-level bureaucrat.
Paraguay would get about $40 million a year from Uruguay for the power, minus the transmission costs.