A Liberal Democrat assembly member has accused party leader Nick Clegg of developing a "blind spot" over party policies for Wales.
South Wales West AM Peter Black has said that the deputy prime minister is not communicating positive messages properly.
Mr Black made the comments in his blog.
He said it "would just be nice" if commitments such as to a full law-making Welsh parliament were talked about "a bit more".
It follows a "slip of the tongue", in which Mr Clegg appeared to say that the UK government supports a yes vote in a referendum on more Welsh assembly powers.
Mr Black, an AM since the Welsh assembly was set up in 1999, wrote: "Clegg does appear to have developed a certain blind spot when it comes to Wales in recent weeks, missing the opportunity to make obvious points to reinforce our party's strong support for fiscal and political fairness on a number of occasions," he wrote.
"It is a blind spot that needs to be corrected soon before it is misinterpreted and used to undermine the Welsh Liberal Democrats' longstanding commitment to a full law-making Welsh parliament and reform of the Barnett formula.
"These feature in part in the coalition agreement. It would just be nice if the Liberal Democrat leader talked about them a bit more."
Mike German AM, the former Welsh Lib Dem leader, who is to leave the assembly to join the House of Lords, said: "Peter Black is known for his strong views.
"Part of my new job will be to ensure that the Welsh voice is clearly heard, and that there's a strong connection between both ends of the M4".
BBC Wales understands that Mr Clegg disappointed some party members last weekend with only a flying visit to the Hay literary festival in which his speech made little reference to Wales, and he spent relatively little time with Welsh activists.
On Monday, Mr Clegg appeared to support a yes vote whilst responding to a question from the Wrexham Labour MP Ian Lucas in the House of Commons.
He said: "Yes, the government does support a yes vote in that referendum".
But his officials later said he only meant to indicate his support for the holding of the referendum.
A spokesman for Mr Clegg said: "The coalition government fully supports a referendum for Wales on the subject of further devolution.
"It is however a matter for the Welsh people to decide which way to vote in this referendum and the UK Government will not take a position on it.
"The deputy prime minister recognises that what he said in the house... did not adequately reflect the stance of the government."
Mr German added that it was an understandable slip of the tongue by Mr Clegg, since as leader of the Lib Dems, he would naturally express his party's strong support for a "yes" vote.
But as a senior figure in the coalition he had to stick to the government's position of neutrality.
Prime Minister David Cameron says the vote should be held in 2011.
Cardiff North Conservative MP Jonathan Evans said Mr Clegg had been speaking in the context of a coalition government and in that case he had made a mistake.
'Very, very happy'
But he added: "For Conservative members, there will be a free vote (on the referendum) and the party's remained neutral.
"Nick Clegg has always been in favour of these additional powers. That's the position of the Liberal Democrats.
"But we're talking here about a coalition government. When Nick Clegg is at the dispatch box, he's answering on behalf of the coalition, and that's a mistake he made."
Mr Evans added he would support a 'yes' vote in any referendum on further powers for Wales, with a few provisios.
"I'm very, very happy to vote yes provided I can be reassured that the ambition of Carwyn Jones and and the people who are going to exercise power in Cardiff Bay is to see that power devolved downwards to local communities," he said.