Wealthy individuals and private equity houses eyeing Aston Martin are finalising bids for the luxury car maker.

The UK marque is being sold by Ford in an auction process managed by investment bank UBS, which has asked for final offers by Tuesday. Bidders are expected to have to pay above £550m to drive away with the goods.

Australia's richest man, James Packer, recently emerged as a bidder, heading a consortium of financial investors. He faces other high-powered players including private equity groups Permira and Doughty Hanson, along with the Canadian parts maker Magna. Sources add that there are other interested parties but declined to say who they were.

There has so far been one round of bidding, with sources indicating offers of more than £450m are on the table. However, observers close to some bidders say they have discovered problems during due diligence, such as a £7m pension deficit that could affect valuation, pushing it down to £400m.

Ford is selling Aston Martin as it struggles to cut capacity and restructure operations. Last week it announced the biggest annual loss in its 103-year history, totalling $12.7bn.