Altron CEO Mteto Nyati says the globalisation trend that benefited the world economy for decades is "under threat" from nationalist leaders and policies.

Nyati, who took over as head of the information and communications technology (ICT) group in April 2017, singled out US President Donald Trump, the UK's "Brexit" movement, and French politician Marine Le Pen.

He was addressing local and foreign lawmakers and industry peers at the International Telecommunication Union (ITU) Telecom World congress in Durban. The event is being held in Africa for the first time.

Nyati said there was a new "agenda of exclusion ... and hatred and fear" and that this was a major cause for concern.

These were forces that went against the ICT sector, which promoted inclusion, he said, adding that "we need to take a stand" for the poor and those without adequate access to information.

He called for a renewed focus on "inclusive growth", saying that "we need bridges, we do not need walls".

Trump has proposed a wall separating the US from neighbouring Mexico, while Le Pen is famously opposed to globalisation and believes that multiculturalism has failed. The UK, meanwhile, is negotiating its exit from the EU.

Nyati was previously CEO of MTN SA and has held senior positions at Microsoft and IBM.

Vestact CEO Paul Theron said in a note on Tuesday that subtle shifts in politics could be "market negative".

"For example, an unexpected electoral outcome which undermines constitutional protections for judicial independence (see Poland) or the value of money (Venezuela) or property ownership (SA) are just not conducive to confidence levels. Populism, government overspending and fiscal recklessness (see the US currently) are also negative, in the long run."

In the UK, domestic-focused stocks had performed poorly since the Brexit vote, Theron said.