The archetypal curate has been accused by Plaid Cymru of a "ludicrous contradiction successful terms" implicit the mode the Welsh authorities is funded.
Plaid’s person Rhun ap Iorwerth has written to Eluned Morgan asking if she would propulsion Prime Minister Keir Starmer to present a caller exemplary to cipher funding.
Mr ap Iorwerth’s enactment deliberation the existent set-up disadvantages Wales and privation it scrapped.
In effect to his letter, Ms Morgan said she would "be pressing for a just approach" to however the existent strategy is applied.
BBC Wales has seen copies of some letters, which were exchanged betwixt the 2 leaders past month.
Public spending is worked retired utilizing the Barnett formula, which dates from the 1970s.
It allocates backing to Wales based connected other spending successful England successful areas specified arsenic health, acquisition and agrarian affairs, which successful Wales are controlled by the Welsh government.
Welsh ministers person a proportionality of England’s further backing based connected Wales’ colonisation size, but determination has agelong been an statement that the needs of Wales’ colonisation should beryllium fixed much value erstwhile the calculations are made.
In his missive to the archetypal minister, Mr ap Iorwerth said: "You person already said that services volition person to beryllium de-prioritised successful 'these pugnacious fiscal times', but I would beryllium grateful for confirmation that successful bid to code underfunding you volition beryllium pursuing a caller just backing exemplary for Wales alongside the consequentials owed to america from the multi-billion lb HS2 obstruction project.
"As I said successful the enclosure upon your palmy nomination, the challenges facing the Labour Welsh authorities are significant. It has been heartening to spot the Senedd precocious ballot successful favour of HS2 consequentials and devolving the Crown Estates – 2 steps that would merchandise sizeable funds to assistance flooded these challenges."
Wales received nary consequential backing for HS2, adjacent though nary of the way is successful Wales, arsenic it is designated an England and Wales project.
The Crown Estate manages the seabed, captious for perchance lucrative offshore upwind developments.
Profits from leasing the seabed is paid to the UK Treasury, which hands a information to the monarchy.
In Scotland, the Crown Estate is devolved, meaning nett revenues are allocated locally.
Replying to Mr ap Iorwerth, the archetypal curate wrote: "In a gathering with the main caput to the Treasury, the furniture caput for finance, constitution and the Cabinet Office explained we are keen to redress the inequities which stay from the erstwhile UK government, and to maximise superior infrastructure concern to enactment the economy.
"We volition beryllium pressing for a just attack to the exertion of the Barnett formula, and a reappraisal of comparability with the Department for Transport, and of Network Rail concern determination processes.”
On devolution of the Crown Estate, Ms Morgan said: “Our programme for authorities and its committedness to devolving the Crown Estate remains unchanged.
"Officials person held archetypal discussions with their UK authorities counterparts connected concern moving with the UK authorities and the Crown Estate to advancement our vigor priorities successful Wales.
"I americium keen to enactment with the UK authorities to advancement the devolution of the Crown Estate to Wales, including knowing the resources we would necessitate to support the transportation of Crown Estate functions successful Wales."
'Beyond comprehension'
In a statement, released connected Thursday, Mr ap Iorwerth said: "Any conception that having 2 Labour governments moving unneurotic would payment Wales has been blown retired of the water."
He added: "The conception that a 'fair approach' tin beryllium adopted to the exertion of the Barnett formula, arsenic suggested by the caller Labour archetypal minister, is simply a ludicrous contradiction successful terms.
"It’s beyond comprehension wherefore the Labour Party proceed to beryllium wedded to a backing look which they themselves person promised to scrap successful the past."
The Welsh authorities has been asked to comment.
Back successful 2017, successful the build-up to that year’s wide election, the past archetypal curate Carwyn Jones told BBC Wales that the Barnett look would beryllium scrapped.
The party’s predetermination manifesto promised "long-term betterment of however the UK allocates nationalist expenditure to guarantee that it reflects the needs of antithetic parts of our state and that nary federation oregon portion of the UK is unfairly disadvantaged".
Labour’s caller 2024 wide predetermination manifesto recognised that "the Welsh fiscal model is retired of date".
It went connected to accidental that if the enactment won the predetermination it was "committed to moving successful concern with the Welsh authorities to guarantee the model delivers worth for wealth with 2 Labour governments committed to fiscal responsibility".
A Welsh authorities spokesperson added: “We person agelong made the lawsuit that the Barnett look should beryllium replaced by a needs-based backing system.
"We volition proceed to marque that lawsuit and volition enactment with the caller UK authorities to amended the mode the existing backing strategy works.”