Undisputed heavyweight champion Oleksandr Usyk has been ordered by the WBO to begin negotiations with mandatory challenger Joseph Parker.

The Ukrainian, 38, unified the division for a second time on 19 July with a fifth-round stoppage of Daniel Dubois at Wembley Stadium.

New Zealand's Parker beat Zhilei Zhang to win the WBO interim belt in March 2024.

Both parties have 30 days to find an agreement or the WBO will order purse bid proceedings.

Parker held the WBO title between 2016 and 2018, beating Andy Ruiz Jr to claim the vacant belt, but lost it to Anthony Joshua after two defences.

Following defeat by Briton Joe Joyce in 2022, the 33-year-old has won six fights in a row to re-emerge among the title contenders.

Parker was set to face Dubois for the IBF strap in February, but the Briton withdrew on two days' notice because of illness. The New Zealander remained on the card in Riyadh and defended his interim title status with a stoppage victory against Martin Bakole instead.

Parker was an ever-present and vocal figure during the build-up to Usyk's latest success and he watched from ringside as the two-weight undisputed champion put on another masterclass in London.

Usyk said he wanted to rest for "two or three months" after earning his second win against Dubois, but named Parker, Tyson Fury, Anthony Joshua and Derek Chisora as potential opponents.

He has yet to lose in 24 contests as a professional, with 15 victories by knockout.