Motorists with sat-nav systems will soon find their maps dotted with bold green logos, after Asda paid to have all its stores marked on Navteq maps.

Now, instead of a generic supermarket logo, all Asda stores will be clearly labelled with its logo.

Navteq has a 50% share of the market for maps used on portable navigation devices (PDNs), and "significantly more than half" of the satellite navigation maps used on mobile phones, according to Andrew Smith, director of Navteq Media Solutions.

Smith would not reveal the cost of Asda's deal, but said the potential for this type of advertising was huge.

"It is so new it is difficult to find something to compare it with," he said. "But there is a lot of excitement about the opportunities for location point advertising."

Smith said he had held discussions with Tesco, which had resulted in no deal, but talks with the Co-operative had been "very positive" he said. "We have been talking to them a lot at their head office in Manchester."

Later this year Navteq will start using the technology on mobile phone maps to send retailer vouchers to customers in the vicinity of stores.