The handset will use an internet connection to allow users to send 'tweets' or 140-character updates to the service, rather than text messaging. INQ also revealed it hoped the budget handset would be available in time for Christmas.
Frank Meehan, chief executive of INQ, told Reuters: "This can really help open up and drive Twitter use on mobile when usage becomes part of your data package like on the PC."
Ben Wood, research director at consultancy CCS Insight, added: "INQ Mobile was the first to offer an affordable handset that appeals to the connected generation that wants instant access to web services such as Facebook and Skype.
"Other manufacturers are also jumping on the social mobile bandwagon and INQ Mobile needs to exploit its agility to stay one step ahead as it looks to ink deals with more operators," Wood said.