Key Points:

Two oil companies fined a total of $70,000 over an oil spill in Christchurch's Lyttelton Harbour have lost a second appeal against their convictions.

Cometa United Corporation of Panama and Tradewood Shipping Co SAS of Italy were last year convicted and fined for discharging about 400 litres of light fuel oil during a bungled refuelling operation of the bulk carrier Antares in September 2004.

The Antares was on its way from South America to Australia.

The two companies lost an appeal to the High Court last year and appealed to the Court of Appeal in August this year.

The Appeal Court today dismissed the companies' appeals.