The raid in Ecuador caused serious diplomatic tensions
International police agency Interpol says Colombian officials did not tamper with computers which they claim provide proof Venezuela financed Farc rebels.
The hard drives were purportedly seized after a raid on a rebel camp in Ecuador at the beginning of March.
Although Interpol certified the authenticity of the files, not their contents, correspondents say their tests add credence to Colombian claims.
Venezuelan President Hugo Chavez vehemently dismissed the allegations.
He said the report was merely a "clown show" that "doesn't deserve serious comment".
Both Venezuela and Ecuador say that any contacts with the Revolutionary Armed Forces of Colombia (Farc) were solely made as part of a humanitarian effort to free hostages held by the left-wing guerrillas.
Colombian forces attacked the Farc camp located just across the border in Ecuador on 1 March.
The computers they seized contain files which, according to Bogota, show that Venezuelan President Hugo Chavez was personally involved in financing and supplying arms to the rebels.
They also suggest that Ecuador maintained links with the Farc.
The Colombian authorities asked Interpol to check the files after Mr Chavez accused them of faking the documents.
Interpol head Ronald Noble said his team had not analysed the information contained on the drives, as Interpol's remit extended only to certifying the authenticity of the documents, not their contents.
Mr Noble said that deep forensic analyses showed Colombia did not modify, delete or create any files, although it did not always follow internationally accepted methods when handling the computers.
"We are absolutely certain that the computer discs our experts examined came from a Farc terrorist camp," he said.
But he was quick to stress that the fact that the files had not been tampered with did not prove that the information contained within them was totally accurate.
By weighing in and putting its seal of authenticity on the documents, Interpol is in a sense adding much greater credence to the Colombian government's allegations, says the BBC's Americas editor Emilio San Pedro.
Washington has confirmed it believes the files are genuine and that the implications for Venezuela, if it has supported the Farc - which is on the US and European lists of terrorist organisations - could be very serious.
But the files use codes and aliases throughout and nowhere is Mr Chavez mentioned by name.
Senior Farc commander Raul Reyes was among 25 people killed in the attack.
The raid provoked the worst regional tensions in recent years, with Ecuador breaking off diplomatic relations with Colombia.