Workers at the firm Capita, which issues TV licences, are this week balloting for strikes.
The 600 members of the Communication Workers Union (CWU) in Bristol and Darwen, Lancashire, are in a dispute over pay.
Union officials say that Capita is hugely profitable but is refusing to make a decent pay offer.
The wages of some workers are only slightly above the minimum wage.
CWU members have already rejected a two-year offer in a consultative ballot. Some 88 percent voted to reject the bosses’ proposal.
Bristol union rep David Wilshire said, “The company needs to take note of the strength of feeling both in Bristol, Darwen and nationally, and negotiate a settlement that is acceptable.”
Capita made record profits of £364.2 million last year.