BUJUMBURA - Burundi's parliament has authorised prosecutors to investigate two lawmakers who accused a senior member of the ruling party of corruption, an official said.

The assembly a request from Attorney General Jean-Bosco Ndikumana to open a probe into the duo - MPs Mathias Basabose and Deo Nshimirimana - at the centre of a widening scandal that last month saw police detain and beat journalists.

Deputy speaker Onesime Nduwimana said the vote did not amount to stripping the legislators of their parliamentary immunity but would allow the pair to be investigated for fraud and corruption.

"We studied (Ndikumana's request) and we authorised the investigation," Nduwimana said, adding that a decision on whether to strip them of their immunity and proceed with prosecution would depend on the results of the probe.

The basis for the allegations against Basabose and Nshimirimana was not immediately clear, but they come just weeks after Basabose's expulsion from President Pierre Nkurunziza's Forces for the Defence of Democracy (FDD) party.

Basabose was kicked out of the party after he levelled accusations of financial impropriety and judicial tampering against FDD chairman leader Hussein Rajab.

"What is happening is a proof that my accusations against Hussein Rajab are founded," Basabose said on Friday when asked  about the judicial inquiry into him and Nshimirimana.

Nduwimana said Rajab was not a subject of the investigation authorised by parliament but has been named as a prosecution witness.

The case drew international attention in April when police detained some 20 journalists who had gone to Basabose's home for a press conference and beat several who attempted to leave.

The incident was widely condemned by diplomats and press freedom groups but after initially deploring the actions of the police, Nkurunziza's administration gave bonuses to the officers involved.

AFP