World championship leader Marcus Gronholm cast off illness to make the rest of the field look sick on the opening day of Rally New Zealand today.

The Ford driver takes a 13 second lead over arch rival Sebastien Loeb in to the second day of the 11th Round of the FIA World Rally championship based in Hamilton, heading to the King Country, Waikato and Franklin districts.

Gronholm was laid low yesterday feeling none too well but was full of fizz from the get-go today, opening a telling 14-second buffer after tricky morning conditions in the stages in the Pirongia-Waitomo region of the Waikato.

Loeb, the two-time world champion, had some encouragement when he was a smidgeon faster in his Citroen in the repeat stages in the afternoon to remain in contention.

Gronholm's Ford teammate Mikko Hirvonen is third nearly 50 seconds behind while Australian Chris Atkinson, downcast in the afternoon, moved to fourth after he was fastest in the super special stage at Mystery Creek to be a further 32 seconds back.

Atkinson, who complained of a balance problem in the afternoon repeat stages, is well ahead of his Subaru teammate, the 2003 world champion Petter Solberg, who is languishing in seventh.

One of the longest stages in the world rally championship proved decisive in the race for honours in the Production World Rally Championship, with the four leaders all running into major problems in the second pass over the 43km Waitomo stage.

Juho Hanninen (Finland, Mitsubishi), New Zealand hope Richard Mason (Subaru), championship leader Toshi Arai (Japan, Subaru) and title hopeful Mirco Baldacci (San Marino, Subaru) all struck troubles on the demanding stage. This left a surprised Armindo Araujo (Portugal) with the unexpected lead of 33.5s over Ireland's Niall McShea who recovered from his own troubles in the morning.

Most focus was at the top of the table, especially with the remarkable start made from Gronholm in slippery morning conditions, in which tyre choice was the key.

"We made a wrong choice of tyres in the morning. Losing seven seconds to Marcus was not good in the first stage but he was much faster than everyone," Loeb said.

Finland's Gronholm said conditions played into his hand as first car on the roads.

"The rain last night definitely helped me running first on the road. Tyre choice could be an issue later but now it is okay."

No doubt his fast form helped his overall health.

"I am feeling quite okay now. Yesterday I was not feeling well at all but now it is better."

Loeb bounced back being fractionally faster than Gronholm in the repeat run through the 20.38km Pirongia West and 43.88km Waitomo stages.

"I don't know whether we have taken enough, but we have been pushing like hell and Marcos is doing the same. It was much better this afternoon."

Atkinson went through a range of emotions after a solid start, a worrying afternoon which was brightened when he was fastest on the super special stage at Mystery Creek, after early believing his Subaru had lost it's balance.

He is 32 seconds behind Hirvonen and has the slight chance to pressure the No 2 Ford driver over the weekend.

The Waitomo stage unleashed a monster late in the day when the WRC cars exposed a rock on the stage - with the leading PWRC drivers all left with little alternative but to drive over it. This produced punctures to leader Hanninen, second placed Mason and also championship leader Arai while another title hopefully Baldacci succumbed to turbo troubles.

That left young Portuguese driver Araujo as the unexpected lead over an even more surprised McShea.

"For sure the afternoon stages were much better. The stages were drying out a lot and we decided not to take such a big cut out of the tyres which worked out. But unfortunately this morning we spun and stalled the engine so it would not be hard to be better than that," said the likeable Irishman.

With Mason's demise the leading New Zealander is Rotorua's Dean Sumner who has a 23 second advantage over Palmerston North's Sam Murray.

There are six special stages tomorrow in the Franklin district and northern Waikato, punctuated with the second super special at Mystery Creek.