High-tech company Oxonica says it would probably need to raise more funds, following the re-listing of its shares on the London Stock Exchange.

The shares had been suspended since April 27, after it lost a key contract with Turkish state oil company Petrol Ofisi. They fell by more than 50 per cent after the company's announcement.

Trials had failed to show any definite savings when Oxonica's fuel additive Envirox was added to high-sulphur diesel.

New trials will now start with low-sulphur diesel, which will become the main lorry fuel in Turkey from July 2008, and which is being used successfully by buses in the UK.

Oxonica made 13 people redundant at its headquarters at Begbroke Science Park, near Kidlington, when it lost the contract and now has less than 30 staff.

It has £2.6m cash reserves and says the cost-cutting means its annual spending has reduced from £900,000 to £650,000.

However, it said a financial review was expected to show that the company would need to raise funds in the next few months with a share offer.

Oxonica's shares on the Alternative Investment Market had risen in the past two years after successful tests of Envirox, which improved fuel consumption in Stagecoach buses. Stagecoach owns two million shares.

The Oxford University spin-off is also in dispute with Neuftec, a company based in the Dominican Republic which claims to have invented Envirox. Oxonica has filed a patents suit in London's High Court to protect itself against the claims. Neuftec has said that it will counter-claim.

As well as Envirox, Oxonica has also developed a suncream additive, Optisol, used by Boots and other manufacturers. It specialises in making nanoparticles, the size of just a few atoms, which have special properties.

Charles Eld, former managing director of Morrells Brewery in Oxford, and Richard Farleigh, the Australian businessman and star of BBC2's Dragon's Den, invested £1.5m to set up the company in 1999 to commercialise the work of Prof Peter Dobson and Dr Gareth Wakefield, of Oxford University.