Prosecutors at the International Criminal Court have accused former Congo vice-president Jean-Pierre Bemba, his former lawyer and three other allies of corrupting witnesses in an attempt to secure his acquittal.

Mr Bemba, already on trial at court in The Hague for crimes against humanity, and his ex-trial lawyer Aime Kilolo Musamba are charged with coaching witnesses and paying them to testify in his favour between 2011 and 2013.

"Mr Bemba directed a plan to see his acquittal through corrupted means," prosecutor Fatou Bensouda told the court, adding that witness testimony, phone and money transfer records and logs from the court's jail would prove her case.

Some of the court's highest-profile cases have collapsed due to witness tampering. Last year, prosecutors abandoned their case against Kenyan President Uhuru Kenyatta, accused of fomenting pre-election violence, because of what they said was large-scale intimidation and bribing of witnesses.

Jean-Jacques Mangenda Kabongo, another member of Bemba's legal team; Fidele Babala Wandu, a politician and close associate of Bemba; and Narcisse Arido, a witness in Mr Bemba's main trial, face similar charges. All five are citizens of Democratic Republic of Congo.

Mr Bemba and his four co-accused deny the charges, saying any payments were intended to cover witnesses' expenses and not to influence their testimony.