Plaid Cymru ministers say they want extra cash for railways and public services in Wales ahead of the UK government's Budget on Wednesday.
Welsh Finance Minister Elin Jones called for the Chancellor John Healey to set out a spending plan that "finally treats us fairly".
The Budget announces Westminster's tax and spending plans for the year ahead - and more cash given to English public services could result in extra spending in Wales where they are devolved.
A UK government spokesperson said the chancellor would focus on giving households and businesses "a bit of breathing space where we can".
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