The Public and Commercial Services is ramping up pressure with more Border Force strikes.
Around 1,000 PCS members are set to strike at four UK ports from 17-20 February.
Even before these take place, a fresh strike date was announced.
Around 100,000 members in the civil service and public sector will strike on 15 March.
This coincides with Budget Day.
The PCS national executive agreed to escalate action.
It says there has been no progress on demands on pay, pensions and job security.
The Border Force strikes will be joined by striking workers from the DVLA, DWP and from the Animal and Plant Health Agency throughout February.
