The Welsh nationalists launched their campaign on Tuesday on the site of the new national assembly building in Cardiff Bay.

The party will campaign on the slogan "a new beginning for Wales" and will publish its manifesto next week.

It is expected to set out a programme of improvements in job creation, education, the health service and public transport.

Dafydd Wigley: "Ready for government"

The party says those priorities are things that could be achieved within the first four-year term.

Plaid Cymru President Dafydd Wigley said: "Plaid Cymru, the party of Wales, has looked to his day since we were first founded.

"We have done our homework, we are ready to take responsibility of government.

"We must make the national assembly work for everyone in Wales for the very simple reason that the national assembly is fundamentally relevant to everyone in Wales."

Opinion polls have suggested that Plaid Cymru, which has four MPs at Westminster, is running in second place to Labour.

A poll for The Western Mail, carried out last month, said Plaid Cymru had 21% of the first-past-the-post vote and 29% of the "top-up" vote.

Ynys Mon MP Ieuan Wyn Jones, the party's campaign manager, said: "In the final month of the campaign we intend to build on the gains of the last year.

"We have fully established ourselves as the only credible alternative to Labour in Wales, and now we are ready for the final push. We are reaching out to the whole of Wales, with our greatest growth, in fact, being in urban and industrial areas.

"We will be fighting a positive campaign, and on the issues that matter - how we can make the national assembly work for the benefit of the people of Wales."

The elections will be held on 6 May

The nationalists' campaign has already come under attack from Labour.

Labour's campaign manager Peter Hain said: "Nobody should be fooled by Plaid Cymru's cuddly words.

"The nationalists stand for one thing and one thing only: separating Wales from the rest of the UK.

"That's what their talk of a 'new beginning' actually means."

The elections to the National Assembly for Wales will take place on the same day as those to the Scottish Parliament, on 6 May.

However, unlike the Scottish Parliament, the assembly in Wales will not have the power to raise taxes or make its own laws.

The assembly, led by a first secretary, will inherit most of the powers currently administered by the Welsh Office.

Out of the assembly's 60 members, 40 will represent constituencies while the additional 20 "top up" members will represent regions.