By Luis Jaime Acosta and Balazs Koranyi
BOGOTA/OSLO (Reuters) - Colombia's government and Marxist rebels will start peace talks as planned on Wednesday in Oslo in a bid to end nearly half a century of conflict after logistical problems delayed departure of the delegates, Colombia's government said.
President Juan Manuel Santos, facing criticism on security issues, has launched the latest attempt to negotiate a deal with the leftist Revolutionary Armed Forces of Colombia (FARC) guerrillas.
"We're leaving now with hope, with moderate optimism. We don't believe in false expectations," said Humberto de la Calle, head of the government's negotiating team, before boarding a plane at a military airport in Bogota with the rest of the team.
"We do believe that there are structural elements that give hope and the idea that we will bring good news to Colombia."
The two sides agreed in August to begin negotiations in Oslo in the first two weeks of October before moving to Cuba for the substantive part of their talks - the latest attempt after several failed peace negotiations since the 1980s.
It was not immediately clear whether the FARC delegation had left for Norway. The parties had been expected to arrive in Oslo last weekend for preliminary meetings, but their departures were delayed by heavy rains in Colombia and other problems.
De la Calle, a former vice president, said the negotiating teams would meet behind closed doors on Wednesday to work out logistics for the official installation and a press conference on Thursday.
The two parties would move to Havana "very soon" after meeting in Oslo, he said without elaborating.
He asked the press for patience and discretion and said information would be provided only through official statements.
FARC leaders have said there were delays in lifting arrest warrants for some delegates. News reports in Colombia indicated a conflict about the composition of the FARC delegation, particularly the inclusion of Dutch national Tanja Nijmeijer.
A spokesman for Interpol said Colombia had asked for the lifting of so-called "red notices," much like arrest warrants, on several FARC members.
Colombia controls only its own notices, and there is a "red notice" filed by the United States for Nijmeijer, alias Alexandra, which has not been lifted, the spokesman said.
In a statement published on Monday, the FARC insisted it had the right to select delegation members, and said Nijmeijer would take part. It is believed she would take part in the Cuban leg of the talks.
While security has improved since a U.S.-backed offensive against FARC rebels and drug barons began a decade ago, the security forces have been unable to land a decisive blow. That has left Santos vulnerable ahead of elections in 2014.
Negotiations in Oslo are expected to focus on laying the groundwork for the later discussions in Cuba, which would focus mainly on land, drugs and political participation issues.
Norway and Cuba have agreed to act as guarantors at the talks while representatives from Venezuela and Chile will also be present.
(Reporting by Balazs Koranyi and Anna Valderrama; Additional reporting by Helen Murphy and Jack Kimball in Bogota; Editing by Alison Williams and Todd Eastham)