People in north Wales do not feel devolution is working for them, a Labour leadership candidate has said.
Lisa Nandy joined Sir Keir Starmer, Emily Thornberry and Rebecca Long Bailey at a hustings in Cardiff on Sunday.
All four supported boosting devolution, with front-runner Sir Keir arguing for a federal UK.
But Ms Nandy said her party may have to fight for devolution in parts of the country "turning away from Labour".
The leadership contest follows a general election where Labour lost six seats in Wales - all with the exception of one were in the north.
Meanwhile Ms Nandy and Ms Long Bailey said they would not stand in the way if a future Welsh Parliament wanted an independence referendum.
Wigan MP Ms Nandy said people in north Wales "feel very shut out from the centre of power - power in Westminster but also power in Cardiff".
"I think if we are honest, we are going to have to go out and fight for devolution in many parts of the country that have been turning away from Labour for some time," she said.
"In my own constituency in Wigan, people feel that the city mayoral deal where Labour is in power hasn't delivered for them, in the same way it has delivered for Manchester.
"And when I was in Rhyl people were telling me exactly the same thing about devolution for the Welsh nation."
Ms Nandy told BBC Wales she wanted to see power devolved into towns that have not felt the benefits of major cities.
"I think the Welsh Labour government understands this really well, and in the conversations I've had with Mark Drakeford and many AMs, this is exactly what we're trying to do," she added.
Welsh Labour leader Mr Drakeford said he believed Ms Nandy was making a "general point about the way in which people, who live away from where decisions are taken, often feel that those decisions aren't influenced by what matters to them".
"We know that throughout the whole of devolution that we've had to work hard to make sure that every part of Wales feels that the National Assembly speaks for them, that their interests matter to us," he told BBC Wales.
Sir Keir, who had won the vast majority of nominations from Welsh Labour MPs, said more powers should be devolved.
"I would not seek to impose anything on Wales - it's about agreement and working together," he told the hustings.
He said "radical federalism" was the way forward, "where more powers are closer to people". Sir Keir said Welsh Labour needed to be a "bigger part of decision making" in the party.
"We don't hold it close enough," Sir Keir, who represents Holborn and St Pancras, said.
"There are examples of what's going on here that we should showcase as the Labour Party and the difference you can make in power."
Ms Long Bailey, the candidate backed by the pro-Jeremy Corbyn group Momentum, said she would want a discussion with Welsh members about devolution.
"It's not a question of what powers would you like to have from Westminster," she said.
"It's an assumption that Wales gets all the powers it needs from Westminster and then it decides which ones it wants to share," the Salford and Eccles politician added.
"We've got to defend the current settlement that we have, and we've got to make the case against this government which has imposed up to £4bn of cuts on the Welsh assembly since 2010."
There was criticism of how the UK party had dealt with Wales, from Emily Thornberry.
She said she had not been briefed, when she was due to do a TV interview in Wales, on what the impact of Labour's promise of free broadband would have been for the country.
The Islington South and Finsbury MP, who appealed to members to help her get on the final ballot, added: "I remember coming down on the train with Welsh Labour when we were going to the manifesto meeting and quite frankly they hadn't been involved early enough at all.
"We do need to have a bit more respect for each other and frankly I think London has not had enough respect for Welsh Labour".
Analysis by BBC Wales political correspondent Paul Martin
With six Westminster seats lost here in December and a Senedd election on the horizon next year, Wales is a priority for the next Labour leader.
This was the only Welsh hustings of the three-month leadership contest and the candidates tried to outdo each other today with praise for Welsh Labour and calls for more devolution.
Sir Keir Starmer, the frontrunner, has by far the most nominations from Welsh Constituency Labour Parties (CLPs) and was the only candidate with a welcoming committee awaiting him outside City Hall.
But Rebecca Long Bailey, seen as the candidate closest to Jeremy Corbyn, got applause when she talked about "open selections" for Labour candidates, a theme associated with the Left of the party.
It was a point that was rebutted by Lisa Nandy, and amid a warm and apparently friendly atmosphere amongst candidates and members, it was a reminder of the underlying tension that has existed in the party throughout the Corbyn years.
A deputy leadership hustings followed the main event at the venue in Cardiff City Hall.
Angela Rayner said the National Assembly elections would be "difficult for us", referring to a recent poll that suggested Labour could lose seats.
The Stockport MP and deputy leadership candidate said: "I don't think it is irreversible."
"We need to make sure that our parliamentarians and our leaders in London, in Westminster know what's happening in Wales," she added.