Two hundred Port of Lyttelton workers have voted to walk off the job for 24 hours on 11 February, in support of their pay claims.
Talks between the port and the workers' union ended last week with what the union described as only a slight improvement on the port's original offer.
The port is offering a two-percent pay rise but the workers say that is not enough.
Rail and Maritime Union spokesperson John Kerr said the 24-hour walk-out was just the first of a number of planned stoppages.
"We're disappointed that it's come to this but clearly we need to focus everyone's mind and get this thing sorted out.
"We do have 14 days now in which to get round the table and thrash out a deal, and that is our preference."
The workers, who represented about half of the port's employees, had already instituted an overtime ban.
A company spokesperson said some services would continue during the strike but it had yet to assess which ones.
Most staff would still be working and it wanted as much of the port as possible to stay open, the spokesperson said.