French finmin defends growth f'cast after IMF downgrade

* Moscovici: official 0.8 pct 2013 growth f'cast realistic

* IMF cuts view; sees 0.1 pct growth 2012, 0.4 pct 2013

LUXEMBOURG, Oct 9 (Reuters) - Finance Minister PierreMoscovici defended France's growth forecasts after the IMF addedto growing doubts about the government's economic outlook bydowngrading its own estimates.

The Socialist government is trying to forge its fiscalcredibility with a 2013 budget which relies on forecasts thatEurope's second-biggest economy will grow 0.8 percent next yearafter an estimated 0.3-percent expansion this year.

However, private-sector economists widely expect lowergrowth next year. The International Monetary Fund forecast onMonday the economy would grow only 0.1 percent this year and 0.4percent in 2013, cutting its estimates from 0.3 percent and 0.8percent respectively in July.

"We are just discussing our budget in the (National)Assembly and our prospects, our forecast, for growth are ...realistic," Moscovici told journalists on the sidelines of an EUfinance ministers meeting in Luxembourg.

Moscovici has insisted the government has enough politicalwill to stick to its deficit reduction targets even in the faceof growing doubts about its economic outlook.

The government, which has pledged to cut the public deficitto 3.0 percent of economic output in 2013 from 4.5 percent thisyear, will have little choice but to raise taxes or make painfulspending cuts if growth falls short of its forecast next year.

The 2013 budget is already France's toughest in at leastthree decades with 10 billion euros ($13 billion) in tax hikesfor the wealthy and another 10 billion euros in tax hikesaffecting businesses.

Five months into office, President Francois Hollande'sapproval ratings are falling in the face of high unemploymentand growing dissatisfaction with the government's austeritydrive.

On Tuesday, thousands of protesters took to the streets inmajor French cities, in marches against austerity called by thehardline CGT union.

($1 = 0.7711 euros)

(Reporting by Leigh Thomas; Editing by Elaine Hardcastle)

((leigh.thomas@thomsonreuters.com)(+33 1 4949 5143)(ReutersMessaging: leigh.thomas.thomsonreuters.com@reuters.net))