The BBC and ITV say they are committed to ensuring Wales is better represented on UK television screens.
A Wales Broadcasting Committee report for the assembly said broadcasters fail to reflect Welsh lives and issues in their programming across the UK.
The BBC said it aimed to make 17% of all network productions in Wales, Scotland and Northern Ireland by 2016.
ITV said it had recently held meetings with a large number Welsh independent production companies.
The committee was asked to look at issues like content, public service broadcasting, and digital switchover.
It said Wales was the "invisible nation" in network programmes and recommended more Wales-based production from channels and closer links to be developed between Welsh ministers, broadcasters and regulators.
The AM who chaired the inquiry, Alun Davies, said references to Wales were largely missing from the main television channels - BBC, ITV and Channel 4 - and it was "no longer acceptable".
"If you watch TV day in day out, week in week out, you won't see Wales represented anywhere across the UK networks and that's a failure," he said.
Rhodri Talfan Davies, head of marketing, communication and audiences at BBC Wales, said the corporation accepted it needed to better reflect every part of the UK in its output.
"I think the point I would make is that we're not sitting around wondering how to do that," he said.
"We're getting on with the work and I think certainly the picture in Wales is a very encouraging one."
He said BBC Wales-made programmes like Torchwood, Doctor Who and Tribe show it can make a "very dynamic contribution to the networks".
"And we want to build on that," he said, adding that Wales was also reflected in award-winning BBC comedy Gavin and Stacey.
He also said the BBC Trust wants to see 17% of network productions made in Wales, Scotland and Northern Ireland by 2016.
"That gives BBC Wales room to double the value of network productions made here in Wales," he said.
ITV said it is in discussions with Ofcom and others to address the long-term issues addressed in the report.
"ITV makes the highest level of investment in UK production of any commercial broadcaster and is committed to commissioning the best ideas from wherever they originate," a spokesman said.
"It is important to point out that we work closely with other broadcasters to encourage producers to come forward with their programme ideas and we were encouraged that a large number of Welsh independent production companies attended recent meetings of the ITV's Nations and Regions Production Fund.
"We hope that these meetings will encourage and stimulate producers to put ideas to ITV in the future."
Established in March of this year, the committee was tasked to look at the future of public service broadcasting in Wales in the English and Welsh languages, assess the impact of the digital switchover and examine the production and availability of programming and digital content from Wales and in Wales.
The document, agreed by a committee of AMs, concluded: "No UK network lives up to its boast that it reflects the lives of people throughout the UK.
"Each UK PSB (public service broadcaster) is, in different ways, London-centric and everyday life in Wales is reflected nowhere, in any genre at any time on the schedules".
The report recommended that industry regulator Ofcom and the assembly government monitor BBC progress towards ensuring 5% of its UK programmes are made in Wales by 2016.
The BBC Trust said it will be studying the report and "will pay particular care to any suggestions that appear to impact on the independence of the BBC."