Labour leader Jeremy Corbyn backed a plan to boost the shipbuilding industry in Belfast as he visited Harland & Wolff shipyard.
Earlier on Friday Mr Corbyn crossed the Irish border after meeting business leaders in Londonderry to hear their concerns over Brexit.
Mr Corbyn walked across the bridge linking Strabane in County Tyrone and Lifford in County Donegal.
He began his visit on Thursday with a speech at Queen’s University Belfast.
Speaking at Harland & Wolf, Mr Corbyn said he backs a £1 billion naval procurement budget going to the UK shipyards, including in Belfast, to sustain the shipbuilding industry.
Jackie Pollock, Unite NI’s regional secretary, said: “Unite welcomes the commitment reiterated by Jeremy Corbyn while he visited Harland & Wolff that these contracts will be allocated to UK ports including Belfast.
“We are now calling on the UK government, as well as all the local political parties, to step up to the plate and adopt a proactive approach to securing these contracts and a future for workers in Belfast and other UK ports.”
First trip to Northern Ireland
Earlier on his first trip to Northern Ireland Mr Corbyn told the BBC that he would take a neutral position on a border poll if he was prime minister.
He also said he would not support a deal that includes a return to a hard border.
The UK and EU have agreed that there will be no hard border, but are at odds on how to achieve that.
A major sticking point is what arrangement will be put in place if the border issue cannot be solved in an overall deal.
Analysis: Corbyn faces tricky questions on post-Brexit border
By Enda McClafferty, BBC NI political correspondent
Jeremy Corbyn was left in no doubt what those at Friday morning’s business event in Derry wanted post-Brexit when they were asked for a hands up on staying in the customs union and single market.
The Labour leader faced a sea of hands.
He also faced some tricky questions – on how his proposed customs union might differ from the one currently in place.
And he was also pressed about access to the single market under his party’s Brexit plan.
Afterwards the Labour leader travelled to the once heavily fortified border crossing between Strabane and Lifford to see what a free flowing frontier looks like.
Before leaving this afternoon he will also visit Harland and Wolff shipyard in Belfast.
The two sides accept the need for a ‘backstop’ but differ on how it should work.
Mr Corbyn suggested on Thursday that Labour’s proposal for a new comprehensive EU-UK customs union has the potential to prevent communities in Northern Ireland being divided.
The event in Derry was hosted by the city’s chamber of commerce.
The president of the chamber, Jennifer McKeever, said that Mr Corbyn was welcomed to “the city at the heart of the Brexit conundrum”.
She said that businesses in the area were being “hugely resilient and pragmatic” about the Brexit challenges ahead but that “patience was wearing thin” two years after the EU referendum.