New mobile operator Circles.Life has launched in Singapore and is the only one letting subscribers make unlimited calls and send unlimited videos and messages from WhatsApp without touching their monthly data allowance.

Also free is the caller number display, a feature for which local telcos Singtel, StarHub and M1 charge $5 a month for their line-only plans.

"We are here to bring power back to the digital customer," said Mr Rameez Ansar, co-founder of Circles.Life.

The jury is still out on whether the bombast is justified. The Straits Times tried to register on its website but received an e-mail stating there is a waiting time, even though the service has been operational for two months.

At first glance, Circles.Life's mobile plans - all of which are sold separately from the phone - are also not the cheapest.

Such line-only plans are becoming a hotly contested space, with Singtel, StarHub and M1 slashing prices as recently as last November.

Circles.Life's basic plan with 3GB of mobile data and 100 minutes of outgoing calls is going for $28 a month. As a launch promotion, subscribers get 2GB of bonus data.

Similar plans from rivals Singtel, StarHub and M1 are going for $20 to $25 a month.

"We have to be competitive. I'm not going to chase prices," said Mr Rameez. "I want to give consumers the best deal and customer service, and flexibility."

Even at that price, the new kid on the block could give local telcos a run for their money by riding on WhatsApp, said Mr Clement Teo, a senior analyst at market research firm Forrester. All Circles.Life's plans include unlimited WhatsApp use.

United States-based Internet statistics firm Statista estimates that more than 70 per cent of mobile Internet users in Singapore are on WhatsApp. Globally, WhatsApp users number more than a billion.

Circles.Life is the brand of two-year-old local start-up Liberty Wireless, which has an operator licence from the Infocomm Development Authority.

The virtual mobile operator does not own or build physical networks but instead leases mobile network capacity from M1.

The last high-profile virtual mobile operator launch was by Virgin Mobile in 2001, leasing wholesale from Singtel. But it exited Singapore a year later, citing weak market conditions.

Asked what has changed since then, Circles.Life co-founder Abhishek Gupta said: "A lot of technologies are only available now to allow us to... be asset light and focus on servicing the customer. That is something that a lot of mobile virtual network operators had tried but could not do."