Conservative group leader in the Welsh assembly Nick Bourne has appealed to disaffected Plaid Cymru supporters to join the Tories.
Nick Bourne has spent eight years re-branding Conservatives in Wales
Mr Bourne said Plaid members unhappy with their coalition deal with Labour in Cardiff Bay could find a "natural home" in the Conservatives.
Speaking at a Tory conference fringe meeting, he questioned Plaid's right to call itself the 'party of Wales'.
Plaid said the Tories aimed to distract attention from poor opinion polls.
Mr Bourne accused Plaid of forfeiting its right to call itself 'the party of Wales' by refusing to lead an assembly government coalition when it had the chance during the summer.
Mr Bourne said Plaid's decision to form a cabinet with Labour, rather than the Tories and Liberal Democrats, showed it was "unwilling to stand up and be counted and take a lead in government".
He told delegates that the Conservatives made policies in Wales and backed new legislation on issues such as the Welsh language.
Mr Bourne said: "To all those people who feel let down by Plaid Cymru's failure to act as the party of Wales, I say come and join us.
"To all those people who are fed up with Labour's tired policies denying people the chance to move forward with choice, diversity and opportunity, I say come and join us.
"To all those people who see that the Conservatives have changed and offer the prospect of policies that will guarantee excellence in public services, priority for the environment, and a chance to make Wales a better place to live, I say come and join us."
Meanwhile, as speculation continued over the chances of a snap general election, there was disappointment that Conservative leader David Cameron failed to appear as expected at the party's Welsh night on the previous evening.
A spokesperson said it was because of Mr Cameron's "busy schedule".
Reacting to the Tory criticism, a Plaid spokesperson said it was "obvious that they can see that more and more people are starting to support Plaid".
"The Tories are simply trying to take people's attention away from their poor performance in the opinion polls and their internal argument over whether or not they should support a Welsh parliament," he added.