BRATISLAVA, Oct 23 (Reuters) - Slovakia's ruling leftist Smer party pushed a bill through parliament on Monday extending a ban on opinion polls to 50 days before elections, one of the longest periods in the world.

The move, coming before a planned election next February, has drawn strong criticism from opposition parties and political experts who view it as an attempt to silence challengers from new parties.

Slovakia, like other countries in Europe, has seen a rise in new parties in recent years.

Most notably, newcomer activist lawyer Zuzana Caputova defeated Smer's preferred candidate in a presidential runoff in March.

The new bill was backed by Smer and one of its two ruling coalition partners, the centre-right Slovak National Party (SNS), as well as opposition far-right People's Party-Our Slovakia.

It will extend the ban on publishing polls from 14 days, which was already the second longest ban of pre-election poll releases in Europe.

Among others in the world, only Cameroon and Tunisia have a longer blackout period.

The bill's authors, from Smer and SNS, said they aimed to protect voters from disinformation so they can base their decisions on the parties' programmes and activities.

"Political parties use opinion polls to influence public opinions, confusing voters," the bill said.

The longer blackout on polls is the second amendment to election rules this year.

In June, the government rushed through legislation tightening campaign financing rules.

In a statement last month, sociologists at the Slovak Academy of Sciences criticised the polling bill as a "violation of the freedom of speech that gives unfair advantage to political parties - that would still be able to order opinion polls without publishing them".

The socially conservative Smer party, in power nearly continuously since 2006, remains the favorite for 온라인슬롯 next year's election.

It stood at 22% support in a Focus poll on Sunday, followed by Progressive Slovakia/Together at 11.0% and far-right People's Party-Our Slovakia at 10.

/>Of the nine parties that would make it to the parliament, four were sitting just above the 5% threshold.

But Smer has suffered election defeats since the 2018 murder of Jan Kuciak, a journalist who investigated high-level graft cases, and his fiancée, at their home.

The killings sparked mass demonstrations against the perceived impunity to corruption. The protests forced longtime Smer leader Robert Fico to resign as prime minist

/>He was replaced by party ally Peter Pellegrini.

(Reporting by Tatiana Jancarikova; editing by Jason Hovet)