The event at which Labour announces its new leader has been cancelled because of the coronavirus outbreak.
Instead of holding a special conference in London on 4 April, the party will now put on a “scaled-back event” on that day.
Rebecca Long-Bailey, Lisa Nandy and Sir Keir Starmer are the three candidates vying to replace Jeremy Corbyn.
The Liberal Democrats, Plaid Cymru and Welsh Labour have all cancelled their spring conferences.
Ten people in the UK have died after testing positive for coronavirus, with 596 cases confirmed.
After cancelling the special conference, Labour said it was “considering options for what form” the replacement event would take.
A spokesperson said: “This is not a decision we have taken lightly. Our priority is the wellbeing of our members and staff, and ensuring we fully contribute to the collective effort to protect public health.
“We are considering whether upcoming constituency meetings should go ahead and will keep our members fully informed.”
Labour members have been voting since late February for their new leader.
Mr Corbyn announced he would stand down after more than four years in the job, following the party’s poor showing in December’s general election, which saw Boris Johnson’s Conservatives win a parliamentary majority of 80.
Speaking in the House of Commons on Thursday, shadow chancellor John McDonnell promised to “work with the government to protect our people and contribute to the worldwide effort to overcome the outbreak of this virus”.