Plaid Cymru is calling on anyone wanting another EU referendum to back the party in the European elections.
At Plaid’s campaign launch, leader Adam Price said his party was “especially” targeting Labour voters.
He said Plaid Cymru was the only party in Wales “with a chance of winning seats” that “unequivocally” backs a further referendum.
Plaid says Wales should hold an independence referendum if Brexit occurs without a further EU referendum.
Last Friday’s announcement by Mr Price on an independence vote went further than his party conference speech in March.
At the Plaid Cymru campaign launch for the European election in Cardiff on Thursday, Mr Price said: “If we want to make Wales matter in Europe and the world, a vote for Plaid is our chance of making it happen.
“If we want the new Wales that a new politics will bring, we must vote for it.
“We know that Wales matters. Wales matters to millions of our people, in their daily lives. But in the corridors of power in Westminster it doesn’t matter one bit.
“This election is not just about putting Wales – our lives, our problems and our dreams – at the heart of Europe, but bringing in Wales from the margins, out from the cold.”
Plaid has previously said that a cross-party deal between anti-Brexit parties “could have been an opportunity to offer the voters the clearest possible choice at the ballot box” and blamed the Greens in Wales for the two parties failing to work together in the European election.
The Green Party has said no approach had been made to it by other parties.
In the last European Parliament election in 2014, the four Welsh seats were split between Plaid, Labour, UKIP and the Conservatives.
Mr Price said: “We are the only party in Wales with a chance of winning seats in the European Parliament that is unequivocally supporting a People’s Vote.
“For that reason we are appealing for support across the parties. We are saying to progressive people across the political spectrum – join us.
“Our appeal is especially to Labour supporters who, for years, have been in a state of permanent disappointment with the leadership of their party.”
Plaid Cymru’s lead candidate, Jill Evans, first elected an MEP in 1999, said she was “proud and thankful” to be standing for a fifth time.
“Because now, more than ever, Wales needs a voice in Europe and because there is so much potential to build a better future for our nation in Europe.”
“We are the only realistic choice for voters who are looking for a different and a constructive way forward,” she added.
The European Parliament elections in Wales
There are eight parties fighting for four Welsh seats in the planned European elections on 23 May.
Welsh Labour, the Welsh Conservatives, Plaid Cymru, the Welsh Liberal Democrats, UKIP and the Green Party are joined by Change UK and the Brexit Party.
You can find a list of candidates here.
Content provided by the BBC. Original piece can be found here https://www.bbc.co.uk/news/uk-wales-politics-48122227