Murders of farmers in South Africa are at a 20-year low, research by one of the country’s biggest farmers’ organisations claims.

Forty-seven farmers were killed in 2017-18, according to statistics compiled by AgriSA, an association of hundreds of agricultural associations across South Africa. This is consistent with a steady decline since a peak of violence in 1998 when 153 died.

Between 80 and 100 were murdered each year from 2003 to 2011, and around 60 until 2016.

The new lower totals contradict recent reports in Australian and other western media describing white farmers in South Africa facing “a surge in violence’.

The Australian home affairs minister, Peter Dutton, said earlier this year that white South African farmers who wanted to migrate to Australia “deserve special attention” and “help from a civilised country like ours” due to the “horrific circumstances” of land seizures and violence.

His comment prompted a diplomatic row with Pretoria.

The figures have been challenged by other organisations representing farmers in South Africa, but AgriSA said its research was “reliable” and an important contribution to understanding the threat faced by farmers in South Africa.

The chair of the association’s Center of Excellence on Rural Safety, Kobus Breytenbach, said there had been a rise in the number of attacks on farms to 561, from 478 in 2016-17.

But the numbers remain much lower than the 1,068 reached in 2001-02, seven years after South Africa’s first free elections marked the definitive end of the apartheid regime.

Breytenbach, a farmer in Free State province, said the threat to farmers remained high and any decline in murders was due to precautions taken by farmers “to protect themselves and their livelihoods”.

“The rural community has become alert and prepared … They are working with the South African police service and are much more organised than 20 years ago. Everyone is aware of the situation,” he said.

There is fierce debate over the reason for the increase in attacks on farms in recent years. Some suggest it is in line with a general increase in violent crime. Others say it is a consequence of growing tensions between communities.

Land is a focus of deep resentment. According to the Land Audit Report, 72% of agricultural land is owned by white farmers, down from 85% when apartheid ended. Much remains in the hands of the minority Afrikaner community, the white descendants of colonial-era settlers. Of 56 million South Africans, about 8% are white, according to the census.

All major political parties now agree on the need for extensive land reform. In February parliament passed a motion to begin the process of amending the constitution to allow for the expropriation of land without compensation.

Earlier this month the president, Cyril Ramaphosa, told an audience including hundreds of Afrikaners that land reform should not be seen as a threat.

“Let us not see the issue of land as a reason to pack up and go ... The future of the Afrikaner is intrinsically linked to the prosperity of the country as a whole,” he said.

The ruling African National Congress party may be tempted to accelerate expropriation to head off a political threat from Julius Malema, the leader of South Africa’s radical left wing Economic Freedom Fighters party, before elections scheduled for next year.

In 2016 Malema called on his followers to “occupy …. land that was taken from us by white people by force through genocide”.

Johan Burger, a former policeman and expert at the respected Institute for Security Studies in Pretoria, said such heated language could contribute to violence.

“There is more than one incident during which attackers claim that their actions are justified because the victims have stolen the land,” he said.

“What is very difficult to explain is the level of exceptional violence,” Burger said. “One could understand the torture of victims to gain access to a safe or get a PIN number and that may be true in many instances, but there are examples of victims tortured for many hours, sometimes even until death, after information is given up. Some say attackers are motivated purely by racial hatred but it is very difficult to quantify.”

The isolation of farms and the limited protection provided by police are also factors often cited to explain the level of violence in attacks.

Statistics for farm murders also include farmworkers, who are usually not white and who are also often hurt in violent attacks. Dozens of non-white farmers have been killed since 2001.

There are some reports of South African farmers selling up and moving overseas, though no statistics that indicate any substantial emigration.

Caty van der Merwe of Afriforum, a campaign group with specific focus on the rights of South Africa’s Afrikaner minority, said she had “come across lots who want to leave”.

New Zealand was a favoured destination, said van der Merwe, who works with victims of farm attacks. Others move elsewhere in southern Africa.

Breytenbach said AgriSA did not think “the solution was to run away”.

“We believe it is better to stay in South Africa and make a difference here rather than to run away overseas, though it is clearly everyone’s right to make their own decisions.”