South Africa's Sasol on Monday posted a 22 percent rise in first-half profit, boosted by cost cuts and higher oil and product prices, and said it expects better full-year operational performance.

Sasol, the world's top maker of motor oil from coal, said headline earnings per share for the six months to end-December rose 22 percent to 12.97 rand.

Headline EPS is the main profit gauge in South Africa and exclude certain one-time items.

First-half sales rose to 67.2 billion rand from 58.1 billion in the same period a year earlier.

Sasol declared an interim dividend of 3.10 rand per share.

The petrochemicals group said it expects operational performance to improve in the full year, compared with the previous year, although macro-economic conditions remain uncertain.

Full-year production volumes at its Synfuels unit are expected to be marginally lower due to a major planned outage undertaken in September last year.

Sasol is investing heavily to build up its portfolio, especially by expanding its shale gas interests. The company's total capital and acquisition expenditure for 2011 is estimated at 23 billion rand.

Shares in the company are up 11 percent so far this year, compared with a 1.9 percent rise in Johannesburg's Top-40 index of blue chips.