On Merseyside, where the RRS Sir David Attenborough was launched in 2019 at the Cammell Laird shipyard, hundreds of workers are to be balloted for strike action.
The ballot is to open next week, on Monday 8 July.
The development at the shipyard in Birkenhead comes after several employees were suspended for refusing to cross a picket line.
Members of trade unions, Unite and GMB working at the Cammell Laird on the Wirral Peninsula have refused to cross a National Union of Rail, Maritime, and Transport Workers (RMT) picket line at the shipyard on Tuesday.
Unite has claimed the staff were suspended despite planned talks with the shipyard company to avoid a similar problem.
Cammell Laird has been contacted for a response.
More from BBC News on the yard.