Communications Minister Pat Rabbitte believes Ireland "couldn't afford" to put Grid West underground, if the project ends up being three times the price of a pylon network.
Eirgrid has unveiled an alternative proposal for a high capacity power connection linking Mayo to the national grid, along local and regional roads.
It is expected it would be more expensive than the existing overground plan, which would cost an estimated €240m.
Both suggestions will go before an independent panel for examination, but the Government will have the final say if they are both seen as being viable.
Speaking to 'The Pat Kenny Show' on Newstalk, Minister Rabbitte says cost must taken into account.
"If it is three times, my personal view is that we can't afford that," he said.
"I would ask taxpayers to tell me why it is the wealthiest economies in western Europe from Germany to Denmark to Holland, why is it that Ireland in its straightened economic circumstances, is supposed to put those cables underground?"
Anti-pylon groups are giving a cautious welcome to the proposal of an underground route.