The ballot is the latest move in escalating unrest over pay at the agency which last year saw MCA specialists undertake a campaign of action short of a strike following the imposition of the 2006 pay award, which amounted to a real terms pay cut.

Prospect’s 180 members in the agency are frustrated that promises to resolve disparities between MCA surveyors and comparable public and private sector grades have not been acted on.

The ballot closes on February 27 with the result being announced shortly after. It follows a vote of no confidence in the agency’s Chief Executive, Peter Cardy, passed by members in January.

Prospect negotiator John Ferrett said the fact that a body of dedicated staff, proud of their standing within the global shipping community, felt compelled to consider strike action was an indication of how low morale had fallen.

"Members, including some in key senior positions, are indicating to us that they wish to leave or redeploy. A recent trawl of staff willing to consider voluntary redundancy as part of restructuring proposals taking place at the agency returned a level of interest far higher than anticipated.

"The most experienced surveyors are jumping ship to better remunerated positions and MCA is unable to attract the best talents to fill senior technical posts. Management can no longer afford to bury its head in the sand over these very real pay problems."

If members vote in favour it will be the first time marine surveyors have taken such action, which will cause a backlog at ports across the country. Prospect’s sister union PCS, which represents staff in other coastguard grades, is also balloting its members on pay over the same period.