Speaking at the Mobile World Congress 2014 here, WhatsApp CEO Jan Koum said the voice service will be deployed first for Android and iPhones, followed later by Blackberry, Microsoft and Nokia phones.
"We are going to introduce voice in WhatsApp in the second quarter of this year...I think we have the best voice product out there. We use the least amount of bandwidth," Koum said.
Currently, users can send voice clips in the form of notes. The new service will be live.
Facebook, last week, acquired WhatsApp for USD 19 billion in a deal that is considered to be one of the largest since that of AOL-Time Warner.
Its founder and CEO Mark Zuckerberg is scheduled to speak at the event later in the day today, his first major appearance since the acquisition announcement.
Zuckerberg is expected to speak about the roadmap ahead for the technology sector as an increasing number of new users log onto the world wide web through their mobile phones.
Whatsapp has 450 million users worldwide and claims to be adding one million new users every day.
In the last few quarters, there has been a huge surge in text volumes from platforms like WhatsApp, Tencent-backed WeChat and Line that presents a cheaper alternative to SMS.
The data cost incurred for sending messages through these apps by users are cheaper than those charged by telcos on SMS.
"We are driven by the mission that people should be able to stay in touch anywhere and affordably. Our goal is to be on every mobile phone in the world," he said.
Koum said the Facebook acquisition will not alter his plans to develop the product to reach the next one billion users, adding that the service will be free of ads.