Gavin McGarrigle of Unifor says unionized truckers are frustrated the federal and provincial governments still have not delivered on a promise to establish and enforce a minimum rate of pay for all drivers.
McGarrigle says this is allowing some companies to underpay drivers.
McGarrigle says if government does not enforce minimum pay rates for all drivers soon, he says more than 400 unionized truckers will go on strike.
More than 1,000 non-unionized truckers went on strike in February and 250 of their union counterparts joined them in March, crippling operations at Vancouver-area ports for weeks.
But a deal was reached at the end of March, and drivers went back to work.
The dispute focused on pay, unpaid time spent at the port waiting for cargo, and claims that some companies underpaid drivers.
Neither level of government or management at the port would immediately comment on the union's threat.