Wales will get an extra £755m over five years as a result of money being spent on the HS2 high-speed rail line in England, the Welsh government has said.
Plaid Cymru has campaigned for Wales to get some of the cash under the Barnett formula rules for public spending.
The party accused Welsh Labour of not pursuing a share of HS2's budget, which some have claimed could reach £80bn.
The Welsh government denied the claim, saying ministers had called for a "fair share" of the extra transport funding.
The new high-speed line, linking London to Birmingham by 2026, with routes to Manchester and Leeds by 2033, is officially predicted to cost £55.7bn, according to the Department for Transport.
Jonathan Edwards, Plaid Cymru MP for Carmarthen West and Dinefwr, accused First Minister Carwyn Jones of trying to "pull the wool over our eyes" about Welsh Labour's attempts to ensure a fair share of extra rail funding.
"It's bad enough that Labour MPs from Wales supported the project despite being fully aware that it will suck hundreds of millions of pounds out of the Welsh economy each and every year," he said.
"Now, however, the First Minister and his party have been exposed as having done nothing to back up their rhetoric."
'Significant additional funding'
A Welsh government spokesman rejected "misleading statements" and said ministers had ensured Wales would get extra money as a result of HS2.
"Wales will receive a Barnett consequential of over £755m over the next 5 years because of increased UK Department for Transport budgets, a consequence of the investment being made in HS2," he said.
"The way Barnett works is that we get a share of the departmental spend for transport - not individual programmes.
"The devolution settlement differs for Wales, Scotland and Northern Ireland - for example rail infrastructure is devolved to Scotland and Northern Ireland but not to Wales.
"As a result, the mechanics of the Barnett formula are a bit different for each administration and additional funding is allocated somewhat differently.
"But the fact is that Wales has received significant additional funding over this SR (Spending Review) period as a result of increases in the Department for Transport budget which in large part arise from funding for HS2."