Around 2,200 companies, including Swiss-based ones, are alleged to have made illicit payments to Iraq in the United Nations oil-for-food programme, says a report.
The UN-backed report said that the 2,200 companies reportedly paid out $1.8 billion (SFr2.29 billion). The Swiss authorities said they would follow up on information contained in the document.
On Thursday the Independent Inquiry Committee (IIC), which was set up by the UN, said in its report that the firms would not necessarily have known about the bribes and surcharges.
Several prominent international firms were named on the list.
But it says corruption would not have been so pervasive had there been better discipline by UN management.
This is the fifth and final report into the $60 billion programme, which was set up to ease the effect of sanctions on Iraq following the invasion in Kuwait.
Several Switzerland-based firms have allegedly been named in the report. But all have denied any involvement in the affair, it was reported.
Mark Pieth, a Swiss lawyer and member of the three-member IIC, told the Associated Press although the investigation was not a criminal inquiry, national authorities were free to follow up on the information contained in its final report.
"We will of course help prosecuting agencies start to open cases," he said.
Switzerland has already launched a criminal investigation focusing on four people connected to the oil-for-food programme in Iraq, the economics ministry said on Thursday.
In a summary of its activities to help the UN investigation so far - not including Thursday's UN report - the ministry said no charges had been filed and gave no details or names.
Switzerland has frozen bank accounts in connection with the investigation, it added.
The country will also follow up on information contained in the UN-backed report, said the ministry.
Swiss authorities have already fined one unnamed company SFr50,000 over the oil-for-food affair.
About 170 files have been handed over as part of the inquiry and interviews conducted with more than 30 representatives of banks, oil dealers and other companies in Switzerland, said the ministry.
Most Swiss companies investigated "cooperated willingly and efficiently" it added.
The oil-for-food programme was established in 1996 to help Iraqis suffering under UN sanctions imposed after Iraq's invasion of Kuwait.
It allowed Iraq to sell oil, provided most of the proceeds were used to buy humanitarian goods. It has since become the target of several corruption investigations.
The Swiss Federal Banking Commission has reviewed the activities of Swiss-based banks during the oil-for-food programme and published a report on its inquiry on Thursday.
The commission "concludes that, on the basis of the information it has reviewed, the due diligence obligations applicable to the banks have not been violated", but it will reinstate its inquiry if the UN-backed report contains new details.
swissinfo with agencies
The UN oil-for-food programme ran from 1996 to 2003.
The report said that under the programme Iraq sold $62 billion of oil to 248 companies.
In return, 3,614 companies sold $34.5 billion of humanitarian goods to Iraq.
In total illicit payments of $1.8 billion are said to have been paid out to the Iraqi government during the oil-for-food programme.