The number of strikes last year in South Africa hit a five-year high, the labour department said on Wednesday.

A total of 99 strikes were recorded in 2012, close to half of them unprotected or illegal strikes, and many of them characterised by violence, Department of Labour director general Nkosinathi Nhleko told journalists in Cape Town.

Tabling the latest Industrial Action Report, which covers the 2012 calendar year, he said strikes over the period involved 241 391 workers, cost the economy 3.3-million working days, and resulted in workers losing R6.6-billion in wages.

The trend was continuing into this year.

"From what we can all see, there is a continuation of the trend we experienced in 2012," Nhleko said.

However, no figures were yet available for the current calendar year.

Asked why so many strikes involved violence, he suggested this had to do with leadership.

"The issue of how parties in the dispute have got to conduct themselves... hinges largely around the issue of exercise of leadership.

"And when we cite leadership as a factor... it is also informed by the mere fact that when these things begin to happen, it is something that wants to suggest that at a level of exercise of leadership, there is something that has not been handled properly and... accordingly."

This, Nhleko said, was a "worrying point".

He said "social partners" needed to tackle the issue of how to prevent violence during strikes.

According to the report, 99 "strike incidents" were recorded in 2012, compared to 67 in 2011; 74 in 2010; 51 in 2009; and, 57 in 2008.

"South Africa experienced violent, bloody and deadly industrial actions in the mining, transport and agricultural industries.... Out of 99 strikes processed within the department, 45 strikes were unprotected."

The document finds most of the working days lost by industry were in the mining sector (82.4%).

"Wages, bonuses and other compensation issues still remain the main reasons for work stoppages in South Africa during 2012."

Further, most workers involved in last year's labour unrest were members of the National Union of Mineworkers.

Among the provinces, Gauteng -- South Africa's economic heartland -- had the most work stoppages.

"Gauteng experienced 42 strikes in 2012, up from 33 in 2011, an increase of 27.3%."

According to the report, workers still had confidence in the Labour Relations Act, the legislation governing bargaining processes and associated legislation, "[but] most of them believe that the cost of living is too high".

Among its conclusions are that "government needs to take control of the situation and solidify practice and protocol with regard to wage negotiations before the nation's mining sector becomes un-investable [sic] as a result of the strikes...".