(Reuters) - South Africa's Harmony Gold on Tuesday raised its gold output forecast for the year to June 2024 by nearly 5% due mainly to higher metal grades, which will also boost earnings per ton of ore processed and cut costs per ounce produced.

In a production update, Harmony said it expects its full-year gold production to be 1.55 million ounces, up from the initial forecast between 1.38 million and 1.48 million ounces.

Harmony said its all-in sustaining cost - an industry measure - is now expected to be about 920,000 rand ($48,962) per kg of gold, from the previous forecast around 975,000 rand.

This was on the back of higher grades averaging 6 grams per ton, an improvement on the prior guidance of 5.6-5.75 grams per ton.

In the nine months to March 31, Harmony produced 1.18 million ounces, a 10% increase on the same period of 2023.

Record high gold prices, coupled with a weaker rand currency against the dollar, saw the rand price increasing 17% year on year and boosting cash generation, Harmony said.

($1 = 18.7900 rand)

(Reporting by Nelson Banya; Editing by Jan Harvey)