* All four trucker unions sign deal
* Three-week strike had caused fuel, cash shortages
* Rand firms after announcement
(Updates with signed deal, other strikes)
By Wendell Roelf
CAPE TOWN, Oct 12 (Reuters) - South African truck drivers have signed a wage deal to end a three-week strike, the freight employers group said on Friday, putting an end to a walk-out that has hit deliveries of fuel, cash and consumer goods in Africa's top economy.
More than 20,000 truck drivers have taken to the streets in often violent protests since late September, demanding higher wages. At least one person was killed and dozens of trucks were torched by demonstrators.
"The agreement has been signed by everyone. The strike is off immediately," Penwell Lunga, chairman of the Road Freight Employers Association told Reuters.
He said workers have agreed to accept wage increases of 10 percent from March 2013, 8 percent the following year and 9 percent for 2015.
All four transport unions were part of the agreement, RFEA spokeswoman Magretia Brown-Engelbrecht said, although she did not reveal details of the deal.
News of the wage deal helped relieve some of the pressure on the rand . The currency, which tumbled to a 3-1/2 year low on Monday on concerns about weeks of crippling strikes, hit its highest in a week immediately following the news.
Since August almost 100,000 workers across South Africa - including 75,000 in the mining sector - have downed tools in often illegal and violent strikes that have undermined investor confidence and already shaky economic growth.
Moody's also cut South Africa's credit rating last month, citing the government's failure to tackle the industrial unrest that has swept from the platinum and gold sectors into other parts of the economy.
In the diamond industry, striking workers at Petra Diamonds
mines have agreed to return to work while union leaders continue talks with management, the National Union of Mineworkers said on Friday.
Petrol stations have been experiencing delays of up to a day in getting fuel and some have run completely dry, the South African Petroleum Industry Association said on Thursday.
Other affected companies include logistics groups Imperial Holding , Super Group , Grindrod , Barloworld and Bidvest .
More than 50 people have been killed in labour-related protests in the last two months, including 34 shot dead by police at Lonmin's Marikana platinum mine on Aug. 16.
South Africa is home to 80 percent of known reserves of platinum and the price of the precious metal has risen more than 20 percent since the Marikana shootings, the bloodiest security incident since the end of apartheid in 1994.
Striking gold miners rejected the industry's latest wage offer on Thursday. Africa's top three bullion producers - AngloGold Ashanti , Gold Fields and Harmony Gold - have given them until Monday to reconsider.
In a separate dispute, a union representing 190,000 government workers has threatened a nationwide strike from next week. One of the union's provincial branches will meet with employers on Tuesday to discuss the workers' demands.
Around 3,800 clothing workers have also downed tools over wages, the Southern African Clothing and Textile Workers' Union (SACTWU) said.
(Additional reporting and writing by Agnieszka Flak; Editing by David Dolan and Jon Hemming)
Keywords: SAFRICA STRIKES/TRUCKS