Helen Mary Jones has been accused of plotting to oust Ieuan Wyn Jones

But Helen Mary Jones has said she does not want the presidency of the party.

The roles of both assembly leader and party president are currently held by Ieuan Wyn Jones, who announced he would stand down following Plaid's poor showing in May's assembly elections.

Ms Jones was one of four AMs accused of scheming to remove Mr Jones by a party chief - but she has denied that any plot existed.

So far, the two candidates to replace Mr Jones as president have come from outside the assembly - former AM Cynog Dafis and party vice-president and councillor Dafydd Iwan.

This means the jobs of president and assembly leader could be split.

Earlier this week, Rhodri Glyn Thomas - the AM for Carmarthen East and Dinefwr - announced that he wished to lead Plaid's 12-strong assembly group if the new president is not an AM.

Ieuan Wyn Jones resigned as leader after the May elections

Now Helen Mary Jones, who represents mid and west Wales, has announced she will contest the post.

"I would welcome the opportunity to lead that opposition in the assembly in partnership with colleagues at Westminster, in Europe and in local government," she said.

Ms Jones, who previously contested the Plaid leadership in August 2000, said she would lead the group to provide a "challenging, forceful opposition to Rhodri Morgan's moribund, bankrupt New Labour government."

She stressed that Plaid must concentrate on delivering "a proper Parliament, and ultimately self government" to communities across Wales.

Ms Jones added that she wanted to deliver strong opposition in the assembly, alongside a party president who would concentrate on "motivating, inspiring, refocusing and re-energising the party itself".

No vacancy

Ieuan Wyn Jones resigned as Plaid president after the party lost five of the 17 seats it had won in the 1999 assembly election.

He ended his three-year leadership after being told he had lost the support of half of the party's remaining AMs.

Officially, there is no separate vacancy as leader of Plaid in the assembly.

According to the party's constitution, there will only be a separate leader in the assembly if the party president comes from outside the assembly.

Ms Jones represented Llanelli in the last assembly term, but lost the constituency to Labour in May's elections.

Plaid plans to elect a new leader by their party conference in mid-September.