Toyota slashed its full-year net profit forecast by more than half on Friday as Japan's biggest automaker grapples with a strong yen, the impact of the March earthquake and record flooding in Thailand.

The company cut its profit outlook to 180 billion yen ($2.3 billion), 54 percent down from its August estimate of a 390 billion yen, after the Thai floods forced plant closures and caused supply-chain problems.

The latest forecast is also lower than Toyota's net profit of 408.1 billion yen in the fiscal year ended March 2011.

The maker of the Prius hybrid and Lexus forecast global vehicle sales would be 7.32 million units for the year ended March 2012, with revenue at 18.20 trillion yen, less than 19.00 trillion yen tipped earlier.

Toyota posted revenue of 18.99 trillion yen during the previous fiscal year.

Full-year operating profit would come in at 200 billion yen, less than half the 450 billion yen predicted earlier this year, it said.

Toyota, like rival Honda, had withdrawn its earlier full-year forecasts as Thailand's worst flooding in decades forced plant closures, undermining efforts to recover from the impact of the March 11 quake-tsunami disasters.

Its decision to release an updated profit forecast removes uncertainty over the state of the automaker's balance sheet, said Mamoru Kato, senior auto analyst at Tokai Tokyo Research Center.

"The margin of downward revision, due to the impact of the foreign currency market and the flooding in Thailand, turned out to be within our expectations," Kato said.

"We can take it positively that they could show where they are going to land (in terms of earnings)."

The Thai flooding added to an already challenging year for Japan's automakers, in particular for Toyota as it looks to continue a recovery from millions of safety-related recalls.

The March disasters hit Toyota just as it was recovering from a crisis that saw it call back nearly nine million vehicles between late 2009 and February last year because of brake and accelerator defects.

Toyota is seen as particularly sensitive to fluctuations in the yen, which has touched fresh post-war highs against the dollar in recent months, prompting the Bank of Japan to intervene in currency markets.

A strong yen erodes the repatriated profits of automakers such as Toyota and makes their domestically made products less competitive when exported.

Japanese companies have been staging a rebound from March 11, which left 20,000 dead or missing and crippled power-generating facilities, including the Fukushima nuclear plant.

As power and parts supply woes mounted in the quake's aftermath, automakers announced production disruptions domestically and overseas, temporarily slowing output or shutting plants.

Toyota shares lost 0.41 percent to finish at 2,636 yen before the forecast was issued.