Ieuan Wyn Jones is also deputy first minister in the assembly government
Plaid Cymru leader Ieuan Wyn Jones says the party has a "duty to deliver" on the trust placed in it by the public.
He said much had already been achieved in "changing the pattern" of Welsh politics with Plaid's assembly government coalition with Labour.
But, welcoming delegates to the party's spring conference in Cardiff, he also warned against complacency.
He said his party had "more work to do" but Plaid ministers were "working hard" to protect people during the recession.
Mr Jones also urged party members to get "fired-up" before the European election in June, and the next general election.
He said Plaid would continue to "argue the case for a greater voice for Wales in the EU" and "continue to battle for the new Wales".
Mr Jones, who is deputy first minister in the assembly government, was speaking at the launch of a conference where attracting young party activists using interactive technology will be a key element.
Themes include the state of the economy and the push for votes in the European elections.
But other controversial issues could be raised such as Plaid's long-term aim of independence for Wales.
While Plaid is in coalition with Labour in the assembly government, Mr Jones attacked the UK Labour government's economic record.
"Whilst the Welsh government is doing everything in our power to protect the Welsh economy Gordon Brown is planning to cut up to £500m from our budget next year onwards," he said.
Mr Jones said any decision to cut off financial resources was unacceptable and the European elections was a chance to send a message to Gordon Brown.
Helen Mary Jones, deputy group leader of Plaid in the assembly and director of communications, who will go to the conference at University of Wales Institute, Cardiff, on Saturday said: "We have a strong message to put across of Wales playing a full part as a free and equal member of the European Union".
She said they would be emphasising what she says are the achievements of the Labour-Plaid assembly government.
Friday's event consisted of workshops and seminars and the party would not "shy away" from the issue of independence, according to one official.
Ms Jones also emphasised longer-term aims for the party.
"In the end we want to be setting out our long-term vision for an independent Wales," she added.
"Being part of Great Britain hasn't exactly protected us.
"We've had Labour who have supported deregulation of the banks - could we really do a worse job by ourselves?"
An interactive website for the conference was launched by the party, and there was to be a special session on blogging.
A conference programme will be on BBC 2 Wales on Saturday, from 1400-1600 BST.