Jim Beam Homegrown in Wellington has not sold out - the first time this has happened in its seven-year lifespan; 2000 tickets are expected to remain unsold.
Event organiser Mark Wright put the shortfall down to the Auckland bonanza.
"This is a perfect storm of large-scale events; we haven't had this type of clash in the past," he said.
"If you look at Nines, it looks like it is going to be a great event, and Eminem and Splore, so it was always going to have some impact being on the same weekend as well."
Mr Wright was philosophical about the clashes.
"Every now and again this kind of thing is going to happen.
"I don't think anyone purposely wants to clash with anyone else ... It's just the nature of the beast and a busy calendar."
The Mission Concert at Mission Estate winery in Napier was likely to draw a crowd of 11,000 to the 25,000-capacity venue, said chief executive Peter Holley.
"To be fair, we have a slightly smaller audience than we have had in previous years, but we have always said we want to bring different acts into the region to suit different genres and this year's has a smaller appeal."
Mr Holley said a number of events around the country, including Rhythm and Vines, international cricket games and the IRB Wellington Sevens, had also not sold out.
"Whether people are busy, they are fragmented or their discretionary income is smaller - there are probably a number of issues there."
Splore marketing and promotions manager Suzanne McNamara said the event had not sold out yet, either.
"All those other things make an impact for sure," she said. "Although I don't think the rugby league does but whether we have a completely different crowd from Eminem is debatable; there is going to be a small effect even though it is a completely different kind of festival."
Auckland Tourism, Events and Economic Development general manager Rachael Carrol, said the weekend was huge for the region and she expected crowds to exceed forecasted economic benefits.
"It is probably the weekend where we will attract the most number of visitors coming to Auckland since we staged the final night of Rugby World Cup in 2011.
"You're talking about 50,000 people converging on Auckland. That's money into local businesses, so the benefit of these events is very broad reaching from an economic standpoint."
Although the cluster of events might offset ticket sales for some, it increased Auckland's profile, she said.
"There is something fantastic about having events really clustered together that gives that sense of big-city buzz."
Crowded calendar too much
Auckland's bustling events calendar provided too much choice for one Auckland woman, who turned down free tickets to the NRL Auckland Nines and sold her Rapture 2014 tickets to attend the Splore festival.
Ella Brockelsby, 25, was looking forward to a busy weekend in the city watching the league at Eden Park before dancing to rap superstar Eminem at Western Springs.
After problems organising her complimentary Nines tickets and those of friends so they could sit together, plus a bad experience with long queues at Big Day Out, also hosted at Western Springs, she decided instead on the relaxed camping vibes of Splore.
Rapture headliner Kendrick Lamar pulling out was also a factor, she said.
"It was becoming too much of a mission organising people to come to the Nines ... We were trying to organise to sit together and it wasn't really working out.
"After Big Day Out, I didn't really like Western Springs as a venue and also with travelling overseas I thought I would be able to see Eminem again," she said.
"I do wish I could have gone to all of it because I do really want to go to the Nines and Eminem had that been on another weekend."
Ms Brockelsby tried to sell her Rapture ticket on Trade Me but the auction fell through, so she ended up selling to friends.
"Even though I don't really know any of the people playing [at Splore] I am excited about having a fun time," she said
She was looking forward to dressing up for the love-themed event and camping with friends for the three days of the festival at Tapapakanga Regional Park.
Auckland's amazing weekend
Rapture hip-hop festival: With Eminem, Western Springs, tonight, 66,000 people
Lantern festival: Albert Park, tonight and tomorrow night, 100,000+ people
Rugby league nines: Eden Park, today (pool play), tomorrow (finale), 96,000 people
Classic Hits Winery Tour: With Breaks Co-op, Stan Walker and The Exponents, tonight, Villa Meria Estate, Mangere, 6500 people
Splore: All weekend, Tapapakanga Regional Park, 7200 people
