The move follows the recent closure of its agency, Barrett Cernis, after the departure of its co-founder and creative director Ray Barrett.
Metro has called a pitch and approached several agencies.
Karen Wall, the marketing director of Metro, confirmed there would be a pitch but refused to comment further.
Barrett Cernis was appointed in November 2002 to promote Metro's Urban Life readership project. Banc previously held the account.
Barrett Cernis' most recent work for the newspaper was a business-to-business campaign highlighting Metro's nationwide reach by picturing Metro readers positioned on landmarks in UK cities.
Metro, which restructured its commercial team after the recent departure of its commercial director, Justin Farnan, is expected to appoint an agency by the end of June.
A year ago, Metro launched a consumer campaign, also created by Barrett Cernis, using the strapline: "News at the speed of life." The work ran in Newcastle in a bid to raise awareness among the core audience of thirtysomething urbanites.
In the past year, Metro has achieved a circulation of more than one million copies, following the launch of editions in the West Country and East Midlands. It has also reached a readership of two million for the first time, according to the National Readership Survey.
Metro's media planning and buying remains with Starcom Mediavest.