An opposition MP wants to declare Free State and parts of four other provinces “Lesotho’s territory”.
The people of Lesotho, called Basotho, lived in these areas until the 19th Century, when they were seized by Afrikaners – white South Africans.
Many Basotho still live in South Africa, especially in Free State.
The Sesotho language is one of South Africa’s 11 official languages, spoken by about four million people in the country, as well as the two million inhabitants of Lesotho.
“It’s time for what is ours to be returned to us,” Tshepo Lipholo, the MP behind the motion, told Lesotho’s parliament, speaking in Sesotho.
“History has a record of what was taken from our people and that people were killed in the process. It is time to correct that,” he said.
Parliament has adjourned until Thursday when the debate will continue.
In Mr Lipholo’s vision, Lesotho would grow from 30,000 sq km (11,600 sq miles) to around 240,000 sq km (93,000 sq miles).
He said that while this was an issue dating back many decades, he believed it was important to address in the present day because the land would help bring prosperity to the people of Lesotho.
He is the leader of the Basotho Convention Movement, which campaigned on the issue during last year’s election, gaining a single seat, which he holds.
The landlocked kingdom of Lesotho is largely mountainous with limited agricultural space.
The former British protectorate is heavily dependent on the country which completely surrounds it – South Africa.
Over the decades thousands of workers have been forced by the lack of job opportunities at home to find work in South African mines.
The Lesotho government is yet to comment on the issue but it is unlikely to risk antagonising its much larger neighbour by backing it.
Mr Lipholo’s motion is based on a 1962 United Nations resolution that recognised the right to self-determination and independence for the people of Basutoland – as Lesotho was then called.
The view from South African officials is that the motion to reclaim territories some Basotho view as their own does not stand a chance of happening, because it does not enjoy the support of the majority in Lesotho.
One of the key stumbling blocks is the 1964 Cairo Declaration of the Organisation of African Unity, now the African Union, whereby African leaders agreed to recognise the existing borders of their newly independent countries, even if they were drawn up by colonial powers, to avoid stirring up conflict across the continent.
Mr Lipholo has previously told Lesotho media that he also hopes to have the motion discussed in the British Parliament “since it was the UK that gave Lesotho its independence in 1966, without correcting the borders seized by the Afrikaners”.
This is not the first time that Lesotho’s present-day borders have been a topic of discussion. In 2018 a civil group known as the Free Basotho Movement wrote to the Lesotho’s UK embassy to request that the late Queen Elizabeth remove the current frontier – essentially making Lesotho a 10th province of South Africa.
They said this would ensure free movement of Basotho people in South Africa and the perks South African nationals enjoy. That matter is ongoing.