Inner-city Sydney residents may have to wait longer for promised free WiFi and digital signboards, with the council poised to reject the only proposal received after an 18-month process to find a supplier.

The City of Sydney is expected to knock back the sole submission for the country's biggest outdoor advertising contract from OohMedia, following the billboard business's takeover of Adshel and major rival JCDecaux dropping out of the contest shortly after buying APN Outdoor.

JCDecaux and Telstra's revamped payphones with ad billboards. Credit:JCDecaux

The contract, valued by industry sources as worth $300 million to $500 million, has been held by JCDecaux since 1997. It includes kiosks, toilets, bus shelters, communication pylons, seats, bins, advertising panels and, in the latest plan, free WiFi for the public.

A report seen by The Sydney Morning Herald/The Age spearheaded by the council's director of city services said the major changes in the outdoor business industry had left the tender process uncompetitive and recommended cancelling the process.