The European Commission called Wednesday on Athens to challenge media reports that Greek deficit data for 2010-15 may have been manipulated, arguing that doubts about their credibility could prove dangerous for the cash-strapped country.
Greece is on an 86-billion-euro (97-billion-dollar) financial lifeline from the European Union - its third rescue package agreed to with international creditors in five years.
Athens' first bailout request was based on the country's 2009 deficit. But the then-head of Greek statistics office Elstat, Andreas Georgiou, has since been accused of overstating the figure, leading to harsher bailout terms.
Greek prosecutors are investigating whether Georgiou - who headed Elstat until 2015 - should face trial.
The issue has recently given rise to doubts aired in the media about official data published by Athens for the subsequent years, according to EU Commissioner Marianne Thyssen, whose responsibilities include European statistics.
She said that the Greek statistics for 2010-15 have been "fully reliable" and warned that claims to the contrary "may create major damage for the credibility of Greek statistics."
Thyssen called on the Greek authorities "to actively and publicly challenge the false impression that data were manipulated during the 2010-2015 period," while stressing that the statistics office must remain credible and independent.
If Athens fails to act, Thyssen suggested that there could be consequences for its current bailout. The next review is due later this year.
"In due time there will be a judgement on how we continue with the support programme ... and it's up to those who have to judge at the time what will happen," the commissioner said.