The party is staging its Labour Live festival in north London on Saturday, with headline acts including Clean Bandit, Rae Morris, Reverend and The Makers and The Magic Numbers.
Labour leader Jeremy Corbyn will make an appearance on stage, along with shadow chancellor John McDonnell, shadow international development secretary Kate Osamor and Owen Jones, a Guardian columnist and prominent Corbyn cheerleader.
The 20,000-capacity White Hart Lane recreation ground will play host to the festival, dubbed a “mini-Glastonbury”, with Labour hoping it will recreate the success of their general election rallies last year.
Last summer saw Mr Corbyn appear at the actual Glastonbury festival, where crowds chanted the Labour leader’s name.
However, there have been suggestions poor sales could see the party lose more than £1m from Labour Live, with reports earlier this week suggesting only 3,000 tickets had been sold.
It has also been claimed the party balked at six-figure fees required to sign first-choice headline acts, such as grime star Stormzy.
Tickets were originally priced at £35 for adults, £30 for concessions and £10 for children.
They are now £10 and free for under 14s with just two days to go before the event.
Tickets have also been given away for free, along with complimentary travel, through constituency Labour parties and the Unite union.
Labour did not comment on the current state of ticket sales and did not say if refunds would be offered to adults who had paid the full price.
Earlier this week, Prime Minister Theresa May mocked Labour over the festival, telling MPs: “The headline act at Labour Live are the shadow chancellor and the Magic Numbers – that just about sums them up.”