Problems plagued the two-day Neon Lights festival, which saw "technological difficulties" causing crippling queues into the venue on Saturday, and had an artist walk off midway through a set yesterday.

Many festival-goers took to Facebook to express their frustrations over an almost two-hour wait to enter the venue on Saturday, which caused them to miss headline acts such as British electronic-soul group Honne, who took to the stage around 6.15pm.

Day One of the festival saw a sold-out crowd of 7,000, with sets starting at 1pm and ending around 11pm.

While previous editions of the multi-genre music festival have seen it spread across both the main field of Fort Canning Green and the smaller Fort Gate venue, this year's edition - the fourth - was kept to Fort Canning Green. This resulted in a major bottleneck at the sole entrance, with slow security checks and even slower issuing of wristbands leaving many festival-goers stranded outside as big headline acts kicked off their performances.

In response to queries, organisers acknowledged that there were major delays with access into the festival grounds between approximately 5pm and 7pm.

Mr Declan Forde, Neon Lights founder and festival director, said: "The main reason for this is that there were technological difficulties with the new scanning system that we used at the entrance.

"This led to knock-on effects of very long queues and slow entry which were extremely frustrating for those arriving at the entrance. We sincerely apologise for this and acknowledge that we should have reacted more quickly and communicated more effectively to the people in the queues."

Among them was hotelier Tong Jiayi, 30, who was stuck in the queue that stretched from the entrance of the festival to Fort Canning's carpark B for almost 90 minutes.

Ms Tong said: "My friends and I arrived at 5.30pm and expected to queue for half an hour maximum, but we were stuck in the same spot till about 6.50pm, after Honne's set was over... then the queue moved quickly and we were in in 20 minutes. The most frustrating thing was that nobody knew why the queue was not moving at all."

It was a double whammy for Ms Tong, who had bought early-bird tickets in anticipation of seeing American pop star Halsey play yesterday. Halsey pulled out just days before, citing "unforeseen circumstances", prompting many festival-goers to seek refunds.

Ms Tong is awaiting a reply on her ticket refund after realising there was an error in the hyperlinked e-mail address provided on the refund website.

Festival-goer Lim Mee Mee, 26, who queued for more than an hour and missed half of Honne's set, also highlighted the long queues at the food and drink stalls. "We needed to strategise as we wanted to spend all the money we had topped up (into our festival bracelets) at one or two stalls. We did not want to spend more time queueing and risk missing the next set," she said.

Despite the frustrations, some people still enjoyed the festival. Ms Jaime Lee, 26, was overwhelmed with emotion upon seeing British folk rockers Mumford & Sons play in Singapore for the first time.

Ms Lee, who works in marketing, said: "Mumford's songs are a lot about chasing this truth, seeking this light, protecting what you love, and there's a very pure kind of vulnerability in their lyrics. So hearing them live for the first time was really moving.... The banjo speaks to you."

There were no long waits yesterday, as organisers were able to rectify logistical issues.

Along with a slight glitch during Norwegian electro-pop singer Aurora's set when the sound system failed, Australian singer and electronic music artist Nick Murphy's set was also plagued by technical issues. He initially refused to start the set because the sound "wasn't right", then left the stage after playing for less than 20 minutes, prompting the organiser to come on stage and apologise for "an issue with the power cord leading to a shorter set".

• Additional reporting by Prisca Ang