Alun Ffred Jones led Gwynedd Council before becoming an AM

The party, which won control of three councils at the last elections, says it has shown it can deliver better services and keep down council tax.

Plaid launched its campaign on Wednesday in Rhondda Cynon Taf, one of its three councils.

Alun Ffred Jones, the former leader of Gwynedd Council, said Plaid the party had proven it could be trusted to run local government.

The party achieved its greatest success at the local council elections in 1999, which were held on the same day as the first Welsh assembly election.

The success of Rhondda Cynon Taf in turning round that basket case of a council previously led by Labour proves that we can do it Alun Ffred Jones AM

Plaid won the traditional Labour strongholds of Rhondda Cynon Taf and Caerphilly and retained control of Gwynedd.

Mr Jones, now the Caernarfon AM, said it was a challenge to build on that success, but added: "I think we have a good story to tell."

"I think it's been proven over the past five years that you can trust Plaid Cymru the Party of Wales with your local council.

"And you might say, 'well, he would say that anyway,' but the fact is that auditor's report after report has given us a clean bill of health, in contrast to many of the Labour-run councils in Wales over the past 10 years."

'Financially sound'

Among the areas highlighted by Plaid, which held its launch at the Rhondda Heritage Park in Trehafod, were education, the environment, public services and housing.

It wants a new funding formula for schools based on need, and promises to make childcare a priority, particularly in deprived areas.

Plaid said thousands of new jobs could be created in environmentally-friendly areas like waste recycling, and wanted free public transport for everyone aged under 18, as well as those still in education.

The party also wants to scrap council tax and replace it with a "fair" system of local income tax.

Plaid said it would give councils "the right to intervene in areas where the Welsh language is vulnerable, such as a 200% tax on second homes".

Mr Jones said: "I think you have to look at our record.

"For example, we are financially sound. We deliver lower tax levels than neighbouring councils by and large, and our service standards are high, and I think it's that record that we want to impress on people.

"We believe in public services and I think our record proves that.

"The success of Rhondda Cynon Taf in turning round that basket case of a council previously led by Labour proves that we can do it."