Discussions are a prelude to a three-year statutory review by the train company, which operates passenger services between London, the East Midlands, Yorkshire, the North East and Scotland.
Competing agencies are expected to be asked for proposals on how GNER can best capitalise on booming leisure travel markets in advance of the review, scheduled for 2004.
The company spends up to £4 million on ads. The below-the-line assignment, won by Clark McKay & Walpole in February 2002, is not affected but GNER is said to be looking for an integrated solution.
The Chime-owned Roose and AMD currently handle GNER's above-the-line work and have worked to improve public perceptions in the wake of numerous safety scandals in the train operating sector.
GNER chiefs believe they are in a position not only to match, but to exceed service standards offered by Virgin on the East Coast route.
Last year, the company appointed the Northern Foods marketer Clare Field to head its sales and marketing operation, with responsibility for its product and service standards.
GNER was under fire in July for a national press ad promoting the scenery alongside one of its coastal routes featuring a picture of Stepper Point in Cornwall, more than 300 miles away. North Cornwall MP Paul Tyler wrote to Christopher Garnett, GNER's chief executive, to demand an explanation for the mistake. The company described it as "unintentional".