PARIS: Euronext wheat futures rose on Friday to a three-week high as uncertain harvest prospects in Europe underpinned prices.

Front-month September milling wheat on Euronext settled up 1.75 euros, or 1%, at 182.75 euros ($205.45) a tonne.

The contract earlier rose to 183.50 euros, its highest since June 12, adding to gains earlier this week, fuelled by an unexpectedly low estimate of US corn planting.

Volumes were light due to a US holiday and some traders cautioned against seeing a strong upward trend.

Physical wheat premiums in French ports held steady at 1.50-2 euros above Euronext, supported by a lack of sellers due to uncertainty surrounding the harvest, traders said.

In France, soft wheat harvesting got underway last week while winter barley harvesting accelerated, farm office FranceAgriMer said on Friday.

Winter barley was showing extremely varied yields along with good quality, grain group Soufflet said in a harvest update on Friday.

"It's difficult to say what the trend is in winter barley as there are such contrasts, and for soft wheat it's too early to assess yields," a futures dealer said.

Rain in the past month has tempered concern about losses due to a dry spring in Europe, although in Germany showers were starting to raise the possibility of harvest delays.

"Rain this week is not likely to be a problem for wheat, which can shake off the moisture, but it will have to stop in the last couple of weeks before harvesting starts," one German trader said.

Traders expect German wheat harvesting to start in about three weeks. Barley harvesting was underway but has been slowed by rain.