The disruptions in Parliament while President Jacob Zuma delivered his eighth State of the Nation address on Thursday night were an attempt to disrupt and destabilise policy making, an economist said.

"The ugly scenes in Parliament which disrupted the State of the Nation, shows that there are self-serving forces at play on all sides that are threatening to disrupt and destabilise policy making," University of Wits economist Kenneth Creamer said.

"This has resulted in a situation where there is a lack of focus on policy issues and where there is not sufficient commitment to doing what needs to be done to solve the country's economic problems."

Creamer was referring to Economic Freedom Fighters (EFF) being thrown out of Parliament on Thursday.

Fist fights broke out as EFF MPs were dragged out the National Assembly after they tried to stand their ground after Speaker Baleka Mbete ordered them to leave, but security officers dragged them out.

EFF MP Floyd Shivambu confronted a few officers and another fight broke out and some of the protection officers' shirts were ripped off and they stood bare-chested as a result of the disruption.

EFF MPs disrupted Zuma and asked when he would pay back the money in terms of what the public protector found on his private residence in Nkandla, KwaZulu-Natal.

EFF leader Julius Malema, Shivambu and MP Mbuyiseni Ndlozi was also asked to leave the house.

Creamer said that during disruptions like that the poor suffered the most.

"It is the poor who suffer most from South Africa's failure to lift its economy onto a new path of growth and development, evidenced by the stark fact, shown by official data, that the number of South Africans living in poverty has increased since 2010," he said.

Commenting on job creation, Creamer said the 200 000 new jobs created recently was not enough to create jobs.

He said the 200 000 new jobs were not sufficient to make a serious dent in South Africa's structural unemployment problem.

"To create sufficient employment opportunities South Africa needs a step-change in investment levels," Creamer said in a statement.

"The state-of-the-nation did not clearly spell out how South Africa is going to lift investment from current levels of around 20% of GDP to the National Development Plan's target where annual investment is valued at 30% of GDP."

He said to achieve the target a more clear commitment from government that it would do what it took to maximise investment in key sectors like mining, manufacturing and agriculture was needed.

He said that at the moment investment levels were declining, partly as a result of power shortages and difficult global conditions.

He said it was also declining due to a range of negative and confusing signals being sent by government.

"It is not enough to talk merely of the 'relative stabilisation' of the mining sector as President Zuma did during his state-of-the-nation speech, there needs to be a commitment to lifting investment in this sector," he said.

"Public sector investment has been on the rise, but it has failed sufficiently to stimulate, or crowd-in, private sector investment."

Creamer said successful state-led investment should serve as a catalyst for increased levels of private sector investment, but this had not been happening.

South Africans needed to work together to lift investment in the country's future," he said.