Top 500 companies in South Korea have raked in for the first time combined sales eclipsing 700 trillion won in the first quarter. 

According to corporate tracker CEO Score on Tuesday, the sales total for 344 of the country's biggest 500 firms came to 793-point-five trillion won in the January to March period, marking an on-year improvement of 19-point-eight percent.

The largest sales, posted at 143-point-three trillion won, came from the information technology, electric and electronics sector. It was followed by petrochemicals, automobiles and auto parts, insurance, securities, public firms and banks. 

By growth, petrochemicals far outpaced IT with its sales shooting up 41 percent over last year.

Meanwhile, the shipbuilding, machinery and equipment industry as well as the communications sector suffered a decline in sales.

By company, tech giant Samsung Electronics retained the top spot, followed by the Korea Gas Corporation, on the back of rising natural gas prices.

The 344 businesses included in the survey were those that have disclosed their financial statements for the first quarter.