Israeli Foreign Minister Avigdor Lieberman on Monday slammed the decision of the Swiss-based Inter-Parliamentary Union to invite the Palestinian Islamist movement Hamas to attend its 2012 session.
"This is just another example of international hypocrisy," Lieberman told Israeli public radio.
"In all international organisations, the 57 Muslim countries and the many non-aligned nations have the majority and consistently take anti-Israel positions," he charged.
Three Hamas MPs left Gaza on Thursday for the meeting in Geneva, marking the first time parliamentarians from the Islamist movement will attend a session of the IPU.
In a statement, the MPs said they planned to discuss "Zionist crimes against (Hamas) members of parliament, in particular their kidnap and deportation."
Lieberman said there would be no immediate move to withdraw Israel from the IPU, but parliament speaker Reuven Rivlin said he was disappointed the organisation had agreed to host Hamas members.
"The president of the IPU, Anders Johnsson, promised me at a meeting last month in Geneva that he would not help Hamas gain international recognition," he told the radio.
The IPU encourages dialogue between MPs from parliaments around the world in a bid to promote "peace and cooperation among peoples" and "the firm establishment of representative democracy."
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The organisation made no comment on the visit when contacted by AFP on Monday and said all meetings were private.
Speaking at a press event organised by rights group Droit Pour Tous (Right for All) in Geneva, Hamas MP Mushir al-Masri said he was confident the Islamist group would repeat its electoral success in a forthcoming vote.
"We believe in democracy and that's why we are doing are best to prepare for elections," Masri, a member of the Hamas intake that won the last parliamentary vote in January 2006, said via an interpreter.
"The Palestinian people will have the choice.
"I believe that Hamas will win the election. I ask that the US and the EU accept the choice of the Palestinian people."
The delegation will attend an event on Wednesday organised by Droit Pour Tous commemorating three years since the Israeli bombing of Gaza.
Masri and Swiss lawmaker Carlo Sommaruga of the Socialist Party is among the list of scheduled speakers.
Ahead of the visit, Swiss daily newspaper Le Matin quoted Pierre Weiss from the centre-right Radical party and head of the Switzerland-Israel Association condemning the decision to invite "a specialist in the theory of stoning women adulterers and cutting hands off of thieves."
"Mr al-Masri is in Switzerland at the invite of the Human Rights Committee of the Inter-Parliamentary Union," a foreign office spokesman said.
"Switzerland, as host of the organisation, has facilitated the request."