Peter Hain said it was important to see how the coalition worked

He was responding to a Plaid call for Prime Minister Gordon Brown to consider a partnership between the parties in Parliament.

Mr Hain said that Plaid had to demonstrate it could govern responsibly in its assembly coalition with Labour.

He said Labour still intends to "fight" Plaid in the 2008 local elections and the next general election.

Mr Hain said there was a burden of responsibility on Plaid to govern responsibly with Labour in Wales.

"Let's see how they perform," he told the BBC Wales Politics Show.

"We'll be fighting them as our enemies in the local elections next May and in the general election, whenever that is.

"We'll be fighting them door by door and street by street.

"In Wales we are in government together and we'll govern in the interests of the people."

Mr Hain also said that he does not expect the Welsh assembly to gain full lawmaking powers "for some years to come."

Adam Price urged Gordon Brown to 'pick up the phone'

The Neath MP said Labour had been at the forefront of devolution campaigning but the existing powers had still not been fully explored by the assembly and the time was not right for full powers.

"We need to take it step by step, let devolution bed in under this new framework."

On Saturday, Plaid Cymru MP Adam Price called on Prime Minister Gordon Brown to "pick up the phone sooner rather than later".

Plaid strategists believe that an increasing polarisation between the Tories and Labour is likely.

They believe this raises the distinct possibility of a hung Parliament following the next general election.

In the closing speech of the party conference in Llandudno, Mr Price, Plaid's director of elections, warned that we could well see the kind of coalition politics that occurred here in Wales following the assembly elections.

"There have been olive branches strewn across the political spectrum, offers of Cabinet seats to Ming Campbell, Tory grandees leading Government reviews.

"But so far nationalists need not apply. What is he afraid of?

"I've got a message for Gordon, pick up the phone."