Hundreds of dock workers at one of the UK’s largest container ports are beginning a fresh two-week strike in a dispute over pay, which could further disrupt the country’s supply chains.

Nearly 600 members of the Unite union at the Port of Liverpool, which is owned by Peel Ports, will strike again from Monday, after the union said talks designed to resolve the dispute ended “in chaos”.

Unite accused the board of operator Peel Ports of intervening to stop a deal, which it said had been agreed in principle, from going ahead.

Unite’s general secretary, Sharon Graham, said the Unite team had “negotiated in good faith with Peel Ports”. “But the talks ended in farce, with the deal agreed between Unite and senior management being pulled by the board,” she said. “Strike action by our members and with the full support of Unite will go ahead.”

Graham accused Peel Ports of “untrustworthy behaviour” and of attempting to threaten the workforce, saying this had only escalated the dispute.

Unite criticised the company’s decision to issue a formal redundancy notice to 132 workers since the strikes at the port began. It said the proposed redundancies did not make any sense at a time when Peel Ports had stated its desire to expand.

Peel Ports said it was “hugely disappointing” that workers had rejected its improved offer of an 11% pay increase, made on Friday. This was an increase from the previous 10.2% offer made by the company on 4 October.

Liverpool dock workers began their first industrial action in September, hours after the Queen’s funeral, when they rejected a 8.3% pay rise, enhanced with a one-off payment of £750.

Peel Ports’ chief operating officer, David Huck, said: “It’s hugely disappointing that Unite has staged yet another outdated show-of-hands mass meeting which has, very predictably, failed to support our improved 11% pay offer.

Huck added: “This is the highest percentage increase of any port group in the UK by far and would see average annual pay rise to £43,275.”

Peel Ports said it had improved its pay offer six times, and accused Unite of blocking the involvement of conciliation service Acas. Huck called on Unite to give port workers an independent postal vote on the 11% pay offer.

“Our feedback from many, many workers is that they are in favour of accepting but are too reluctant to do so in a mass meeting,” he said.

Meanwhile, BT and Openreach workers will also hold fresh industrial action on Monday as part of a long-running pay dispute.

The 24-hour strike by members of the Communication Workers Union, the latest in a wave of stoppages in recent weeks, will include 999 call handlers.