(Decanter) - There has been a sharp drop in the number of French winemakers converting their vines to organic, but supporters believe consumer demand will spark a fresh growth phase.

France's organic wine sector appears to be nearing a plateau. There were just under 5,000 hectares (ha) of vines in their first year of being converted to organic across France in 2012, but that is down from close to 12,200ha in 2010.

The official figures also show that, between 2007 and 2011, the number of France's winemakers either certified organic or in conversion rose by 145%. But, the increase was just 5% in 2012 alone.

'Producers who have converted so far are those who find it easiest,' Patrick Guiraud, president of organic wine trade body Sudvinbio,told decanter.com. 'We now have to wait for producers who will find it more difficult.'

But, he is not concerned. 'It is normal after very rapid growth there should be a decline in the number of producers converting,' he said following last week's Millesime Bio organic wine shownin Montpellier, southern France.

'It will be consumers who drive the next big wave of producers to opt to convert to organic viticulture,' Guiraud said.

'I’m convinced that this will happen because of increasing awareness of our environment and concerns over pesticides in the water supplies.'