It had been suggested P&O owners DP World might shelve the plan after Transport Secretary Louise Haigh described the ferry company as a “rogue operator”.
But Jonathan Reynolds told the BBC DP World’s plan to expand its London Gateway port “will go ahead”.
The row had threatened to overshadow a major government summit starting on Monday, at which ministers want to showcase investment into the UK.
But DP World will now attend the International Investment Summit, where the government hopes to attract billions of pounds of investment.
The row started after an interview on Wednesday in which Haigh said she had been boycotting P&O Ferries since its decision in 2022 to sack 800 staff and replace them with cheaper agency workers, adding she would “encourage consumers to do the same”.
The company has defended the decision as “tough but necessary,” arguing it was required to safeguard the future of the firm.
Speaking to Sunday with Laura Kuenssberg, Reynolds said his cabinet colleague had not been expressing “the government’s position”.
He added that Labour maintained the sackings were “wrong”, but highlighted that it had now announced plans to tighten legal protections for seafarers.
“It’s now the case that, as we’re in government, we can stop what happened with P&O Ferries happening again,” he added.
Speaking on Sky News, Reynolds said the government had had to “have a conversation” with DP World, following reports the investment would be shelved.
Reynold’s comments came after Prime Minister Sir Keir Starmer also told the BBC’s Newscast on Friday that Haigh’s views were not those of the government’s.
On Saturday a government source said the prime minister had confidence in Haigh. Her department says she will be attending the investment summit on Monday.
Haigh’s comments had coincided with the Department for Transport announcing new legislation aimed at protecting seafarers’ jobs from so-called “fire and rehire” practices of “rogue employers”.
Former Tory donor John Caudwell, who announced he would be voting Labour ahead of July’s general election, said it was “politically stupid” to criticise companies when ministers were seeking more investment into the UK.
The Phones 4U founder told Laura Kuenssberg that ministers should speak to firms privately about their working practices, “rather than just blast them on the TV”.
Haigh’s remarks have also attracted criticism from the Conservatives, with shadow business secretary Kevin Hollinrake arguing Labour “don’t understand business”.
However, Liam Byrne, the Labour MP who chairs the Commons business committee, has defended her comments.
He said Haigh had been “absolutely right to say the behaviour of P&O, owned by DP World, in the past has been “completely unacceptable”.
DP World has said the expansion of the London Gateway port would bring Thurrock in Essex hundreds of jobs.
The United Arab Emirates-based company also owns the container port in Southampton.
A spokesperson for the company told the BBC it had been “given the clarity we need” after “constructive and positive discussions with the government”.
“We look forward to participating in Monday’s International Investment Summit,” they added.
