Sir Keir Starmer visited Wales on Thursday to promote Welsh Labour's coronavirus recovery plan ahead of this year's Senedd election.
The Labour leader was joined by First Minister Mark Drakeford at the Down to Earth Project in Gower, where they said jobs, skills and opportunities for young people are at the heart of their election manifesto.
Pledges include building 20,000 new, low-carbon social homes for rent and developing a Global Centre of Rail Excellence in the Dulais Valley to promote rail innovation and create 300 jobs.
The visit is Sir Keir's second to Wales since he became leader and the first during campaigning for the May 6 election.
During his visit Sir Keir's also defended Labour's record in the Welsh Government.
He said voters should judge Welsh Labour on their "record and ambition".
Sir Keir said: "Mark Drakeford and Welsh Labour have had the right economic plan to get Wales through the pandemic and have the right plan to power the economy with a jobs first recovery. This election is the opportunity to give them the tools to finish that work.
"Wales is a brilliant, bold and optimistic country, and Welsh Labour's guarantee of a good quality job or training for every young person underscores the determination to make Wales the best place in the UK - and Europe - to be young and to have a family.
"Welsh Labour is also building the green economy of tomorrow. Wales is already a world leader in recycling, and I'm determined to work with Mark Drakeford and his team to create green jobs and ensure Wales is a world leader in the green industries of the future."
He also said Welsh Labour candidates who support independence should focus on Covid recovery, instead of calling for a referendum.
Welsh Labour has three pro-independence candidates standing for the election, but Mr Drakeford has ruled out an independence referendum as part of any coalition deal between his party and Plaid Cymru if Labour fails to secure a majority.
Asked whether he was comfortable with pro-independence candidates being allowed to stand for Labour, Sir Keir said: "I want to see a strong Wales in a fair United Kingdom. I think at the moment the absolute focus in politics has to be on the recovery.
"That's why it's core to what Welsh Labour are saying going into this election.
"I know people will have different views on independence. But I think most people would say that coming out of this pandemic the simple and core focus should be on the recovery."
He denied that he could be a "liability" to Welsh Labour's election campaign, after Mr Drakeford received better approval ratings in recent polling than those for him by UK voters.
Sir Keir said Mr Drakeford was held in "high regard" by the Welsh public for the way he had guided Wales through the pandemic, adding that he had no concerns that the Welsh Conservatives may steal voters from Labour by having a stronger unionist message.