A farmer and his wife have been shot dead in another horrific farm murder in South Africa.

Isak van den Berg, 67 and his 62-year-old wife Ina, were allegedly tied up, beaten and killed by a group of six on their Boshof farm in the west of South Africa's Free State province.

Five suspects have been arrested in Bloemfontein and Dealesville during a 72-hour joint lockdown by the South African Police Services (SAPS) and the Hawks, and are expected to appear in court on Thursday. A sixth alleged killer remains at large.

It is the latest in a string of horrific farm murders in the country and comes weeks after 51-year-old farm activist Annette Kennealy was stabbed and beaten to death on her own smallholding in Limpopo province.

A farmer and his wife are the victims of a brutal murder in a farming town in the west of South Africa's Free State province

Five of those who are accused have been arrested in Bloemfontein and Dealesville during a 72-hour joint lockdown by the South African Police Services (SAPS) and the Hawks, and are expected to appear in court on Thursday (stock)

Mr Van den Berg had left his wife to take a worker back to town, according to Brigadier Sam Makhele.

On the way back last Friday evening, he stopped to open his farm gate when he was allegedly overpowered by six suspects.

'He was then taken back to his house where, together with his wife, [he was] tied up, brutally beaten and shot. They both died at the scene,' Makhele said in a statement.

According to authorities, the group of six then proceeded to ransack the property, stealing items including four firearms.

The firearms were later recovered along the Caledon River bed en route to Lesotho.

A neighbour discovered the two bodies in the property's kitchen on Saturday morning.

A pathology report will be conducted this week to determine the exact cause of the deaths.

Sergeant Wendy Nkabi told News24 two strangers had been spotted on the property on Friday before the murders.

According to Nkabi, Van Den Berg had noticed the two strangers when he was giving the worker a lift back into town. The attack started upon his return.

The five in custody face will appear in Boshof Magistrate's Court charged with murder, the possession of unlicensed firearms, aggravated robbery, the theft of a motor vehicle and theft (stock)

The five in custody face will appear in Boshof Magistrate's Court charged with murder, the possession of unlicensed firearms, aggravated robbery, the theft of a motor vehicle and theft.

The killings come just weeks after a South African activist who spoke out against attacks on white farmers was found stabbed and beaten to death on her own farm.

Annette Kennealy, 51, was killed on a smallholding in Limpopo province where she had been staying with an employee, police said.

In her last Facebook post, she shared a link alleging that 10 farm attacks, including one murder, had been reported in four days in 2019.

She also routinely shared links and stories relating to politics in South Africa, and the government's plans to start expropriating farms from white land-owners.

Weeks later, another South African wine merchant was found dead after being shot while dining with family and friends.

Stefan Smit, 62, had been openly critical of the threat of land grabs on his property - a large estate in Stellenbosch, Western Cape - South Africa's most famous wine region.

It was a murder seemingly fuelled by a land dispute created when a squat straddling Smit's Louisenhof Estate was set up, expanding into a vast settlement.

The farmer had previously complained about how citizens from a nearby township had begun erecting shacks at the back of his farm, culminating in him getting an injunction to prevent people from encroaching on his space.

Smit was killed when four men entered his vineyard through an unlocked back door and shot him dead. His wife and a family friend managed to survive the attack.

Transvaal Agricultural Union, a group representing the interests of farmers, recorded 84 farm murders in the 2017 calendar year. Of these, 59 victims were white farmers.

A further 15 people, including eight white farmers, were killed on farms in the first three months of 2018.