IMF chief Christine Lagarde says she sees little alternative to the agenda of austerity being pushed across Europe, after massive demonstrations in several countries demanded an end to the policies.

Asked by journalists from Swiss public broadcaster RTS if there existed any alternatives to austerity programmes, Lagarde answered: "What is the alternative?"

Returning to out-of-control deficits was not an option, Lagarde said, adding that stimulus programmes were impossible as these could only be financed by more debt.

"The situation is difficult," she acknowledged, adding that countries needed to simultaneously observe "budgetary discipline", "prefer elements of growth" and promote "investment in employment".

The challenge was a "fine line" to tread, she said.

The interview was conducted in French on the sidelines of a symposium in St. Gallen in northeastern Switzerland, which each year gathers international decision makers in a sort of mini-Davos setting.

Her comments came a day after tens of thousands of angry protesters staged May Day rallies in several countries of the crisis-wracked eurozone, demanding an end to austerity measures many blame for stagnated growth and spiralling unemployment.

She said Germany -- blamed by many for spearheading the austerity drive -- was "harvesting the fruits of its policies."

She also brushed aside speculation she could be forced to resign as IMF chief due to a brewing scandal over a huge state payout to a disgraced tycoon when she was French finance minister.

"The IMF does not speculate and I don't speculate," she said.

Lagarde has been ordered to appear before a special court at the end of May to answer questions over her handling of a dispute that resulted in 400 million euros ($520m) being paid to Bernard Tapie, a former politician and controversial businessman jailed for match-fixing during his time as boss of leading French football club Olympique Marseille.