The commercial radio industry has enjoyed a rise of almost 5% in advertising growth.

The figures, to be released officially on Wednesday, are expected to show Australian media companies are riding high on the back of a strong advertising market, which has grown 7.9% in 2003 to just under $9.4 billion.

Radio advertising has increased significantly, experiencing a jump of 4.9% in 2003 over the previous year.

Outdoor signage, such as billboards, is the fastest growing sector, up 13.6%, just outpacing cinema. And, television is a key beneficiary of the stronger market (9.9%).

The drive in growth has been attributed to increased advertising from retailers, such as Coles Myer and David Jones, car makers and telcos.

Newspapers had the largest share of the advertising spend in 2003, with 34.7% of total expenditure, up 6.8% on the previous year.