* Sechin is a witness in trial over alleged bribe
* Participated in sting leading to minister's arrest
* Rosneft cites heavy schedule as reason for absence
* Sechin, former minister in rival Kremlin factions (Add detail on an event in West Siberia, quotes, background)
By Vladimir Soldatkin and Katya Golubkova
MOSCOW, Nov 21 (Reuters) - The head of Russian state oil giant Rosneft, Igor Sechin, will not be in Moscow on Wednesday where he is meant to appear in court to testify in a major corruption trial of a former minister, according to Russian news agencies.
Russian prosecutors accuse Alexei Ulyukayev of extorting a $2 million bribe from powerful political rival Sechin in exchange for approving a lucrative business deal in what turned out to be a sting operation.
Ulyukayev, who was fired by President Vladimir Putin from his post as economy minister shortly after being detained, denies the charges and says Sechin framed him.
Asked by reporters whether he would be in Moscow on Wednesday when the hearing is due, Sechin replied that he would be still be on a visit to western Siberia where on Tuesday he attended the opening of a new Rosneft oil field.
"Tomorrow I am meeting with the governor (of the Khanty-Mansiiysk region), gathering the staff, will be summing up results of the prime minister's visit," Sechin was quoted as saying by Interfax news agency.
Sechin has already missed two hearings in Ulyukayev's trial. He has previously said he would attend as soon as his schedule allowed.
Ulyukayev's arrest a year ago came moments after Sechin personally handed him the cash in a late-night meeting at the Rosneft headquarters in exchange for signing off on Rosneft's purchase of a stake in mid-sized oil producer Bashneft , according to investigators.
The fate of Bashneft, one of the most lucrative state assets to be privatised in years, was the focus of a major turf war between rival Kremlin camps, sources close to the deal and in the government have said.
Ulyukayev was among those who believed Bashneft should go to private investors. Both he and Sechin are deeply embedded in the tangle of allegiances and rivalries in Russian politics and business.
Ulyukayev belonged to a faction of economic liberals who argued for less state control over the economy, while Sechin, a close ally of President Vladimir Putin, represents the opposite view.
Rosneft spokesman Mikhail Leontyev dismissed speculation over possible reasons for Sechin's likely absence at Wednesday's hearing, also citing the demands of his schedule.
"This is a made up problem and it was made up with only one purpose - to avoid attention from the essence of the trial," Leontyev said.
"This is not the first case in the human or Russian history when the court wants to hear a testimony of a man with tight schedule."
Ulyukayev faces up to 15 years in jail if found guilty. (Reporting by Katya Golubkova and Vladimir Soldatkin; additional reporting by Polina Nikolskaya and Darya Korsunskaya; Editing by Dmitry Solovyov and Raissa Kasolowsky)