TV and radio in Wales is "failing" and "overly reliant" on the BBC, Plaid Cymru and Labour politicians have said.
MPs and assembly members have written an open letter urging the UK government to devolve power over broadcasting.
They criticise cuts and say there needs to be more scrutiny of the media.
The call came as Wales Office minister Guto Bebb announced details of an independent review of Welsh-language broadcaster S4C at the National Eisteddfod on Anglesey.
S4C receives most of its funding from the BBC licence fee, along with a grant from the UK's Department for Digital, Culture, Media and Sport (DCMS) and the sale of advertising.
Expressing regret over cuts to output and funding of Welsh broadcasters, the letter released by language campaign group Cymdeithas yr Iaith Gymraeg said: "Without a doubt, there needs to be substantially more scrutiny by the media of every level of government in Wales.
"The current system is failing and is overly reliant on one broadcaster.
"Devolving broadcasting is a change which enjoys strong support among the public," the letter added.
Plaid leader Leanne Wood, the party's four MPs and several of its assembly members signed the letter, along with Labour AMs Eluned Morgan and Jeremy Miles.
Albert Owen, the Labour MP for Ynys Mon, did not sign the letter but backed the idea of devolving S4C and broadcasting, "on the condition that it is funded by the Treasury and doesn't impact on other budgets".
The UK government has been asked to comment.