WARSAW (BLOOMBERG) - Poland's ruling party has pressed forward with conducting Europe's only national election during the Covid-19 crisis.

The Law & Justice party muscled its measure to hold the May 10 presidential election only via mail-in ballots through the lower house of Parliament overnight. Poland's human rights ombudsman said this type of sweeping last-minute change leaves the ballot susceptible to fraud.

The events in Warsaw follow last week's passage of a law in Hungary that allows its government to rule by decree for as long as it wants - a development that intensified concern that European leaders are using the cover of Covid-19 to seize more power.

Opposition candidates, who've halted campaigning, urged the Polish government to delay the election and focus on the response to keep the US$586 billion (S$835 billion) economy afloat. The ruling party has been divided over whether to pursue the only-by-post ballot, but the plan's leading critic, Deputy Prime Minister Jaroslaw Gowin, resigned on Monday.

Opinion polls show Law & Justice's candidate - President Andrzej Duda - has surged in popularity as a leader of the nation's virus response. But it's not clear how long he can keep his support as the measures aimed at slowing the spread of the virus push the economy into recession.

SENATE TEST

Other European nations, including Serbia, North Macedonia and EU member Romania, have already pushed back elections originally scheduled for the nearest months, and Russian President Vladimir Putin has delayed a referendum that would let him rule until 2036. France held a vote for local administrations, as did the German state of Bavaria.

The mail-vote Bill also grants the parliamentary speaker flexibility in moving the election by several weeks if the pandemic persists. The measure's passage is set to slow in the Senate, which is controlled by the opposition.

The upper house said it would use the full 30 days it has to debate the legislation, meaning that it would send the draft law back to the lower house - which can override any amendments - just days before the election is due to be held.

"In any vote by mail, special care must be taken to protect against possible fraud and abuse," human-rights ombudsman Adam Bodnar said in an interview. "Such diligence is difficult if such a fundamental change is to be made literally on the eve of the election."