Tamoil, the third largest oil company in Switzerland, is to invest some SFr300 million ($170.45 million) to update its refinery at Collombey in canton Valais.
A management statement said modernisation of the plant was needed to assure its profitability. Some 40 jobs could be created as a result of the investment.
Tamoil, which is part of the Oilinvest group of the Netherlands, said the Collombey plant no longer corresponded to the needs of the Swiss market.
In future it is to concentrate more on refining heavy oils to produce petrol, kerosene, diesel and heating oil.
The Collombey refinery - one of two in Switzerland - employs 170 people and is located at the eastern end of Lake Geneva.
Tamoil has been established in Switzerland since 1990. However, the company's origins date back to 1945 when the distribution firm, Charles Zobrist, was launched in Geneva.
swissinfo with agencies