* Swiss ban money transfers to Gaddafi's associates
* Libyan oil firm Tamoil has refinery in Switzerland
ZURICH, March 4 (Reuters) - Switzerland ratcheted up pressure on Libyan leader Muammar Gaddafi by banning transfers of money that could end up in the hands of his family and associates.
Switzerland is working hard to improve its image as a haven for ill-gotten assets and in February the Swiss government froze assets of 29 Libyans linked to Gaddafi. It has also frozen any assets belonging to ousted Egyptian president Hosni Mubarak.
"Switzerland wants to prevent any financial support of Muammar Gaddafi and his circle," the government said.
It will also be forbidden to give people linked to Gaddafi direct or indirect access to money or economic resources, it added.
The decision could affect Libyan oil company Tamoil, which operates a 72,000 barrel-per-day refinery in western Switzerland.
When asked about the measure's effect on Tamoil, government spokesman Andre Simonazzi said: "With each transaction for Tamoil the question gets raised -- where's the money going? It's got to be investigated who would profit."
But he said it was not up to the government to run checks on money movements. "It's up to the banks and financial institutions."
Tamoil spokesman Laurent Paoliello said on Friday the company would not be impacted by the new measures.
"The decision by the Federal Council confirmed that Tamoil Switzerland is a Swiss company like any other and we can continue to work normally," he said. "It showed that we were neither affected by the U.N. sanctions nor by the Swiss resolution."
Earlier this week Paoliello said that U.N. sanctions could affect the group's ability to source crude and that it was monitoring the impact.
The U.N. Security Council imposed sanctions on Saturday on Gaddafi and his family for his repression of a popular uprising in which possibly thousands have been killed.
Switzerland has not been alone in its moves against Gaddafi. On Friday, Austria widened an asset freeze list to include a top official at the Libyan Investment Authority (LIA), Libya's sovereign wealth fund.
Britain also extended a freeze on Gaddafi family assets to a further 20 members of his entourage and impounded around 100 million pounds of Libyan currency.
Relations between Switzerland and Libya soured in 2008 when Geneva police arrested a son of Gaddafi on charges -- later dropped -- of abusing two domestic employees.
Libya withdrew millions of dollars from Swiss banks, halted oil exports to Switzerland and barred two Swiss businessmen working in Libya from leaving the country.
(Reporting by Catherine Bosley, additional reporting by Emma Farge in London; Editing by Elizabeth Fullerton)