The council wants to mount a public affairs offensive from the end of this month, when consultation ends on Government proposals on the future of UK air travel.
The work by the agency is expected to last until spring, when the Government is set to publish its White Paper on aviation. This is likely to include the Government's preferred locations for additional runway capacity.
Also in the frame are an expansion plan for Stansted, Essex and a new airport at Cliffe, in Kent.
According to council documents leaked to PRWeek, 'the council intends to appoint professional lobbyists to assist in mounting strenuous opposition to Government and key opinion-formers in the crucial period between the end of consultation and the publication of the White Paper'.
The successful agency will also be asked to draw up contingency plans if a ministerial decision is delayed. A delay until the summer is likely.
It is understood that six agencies have already been approached with a deadline set for next week (15 November) to submit proposals.
A council spokeswoman said that so far the council's opposition to the airport expansion was to support efforts at a local level, including the setting up of a community action group.
The lobbying firm appointed will report to the council CEO Dorian Leatham, council leader Ray Puddifott and work alongside head of policy Brian Murrell and PR manager Roy Mills.
Meanwhile Medway Council, which is objecting to the plans at Cliffe, has hired Citigate Communications to handle lobbying around the issue.