THE purported class action lawsuit against the City of Sydney's Bourke Street cycleway has collapsed, with the lawyer involved admitting he acts for one company, not the claimed 102.

John Mahony of Mahony Dominic Lawyers sent a letter of demand to the council on July 30 and claimed to act for 102 businesses adversely affected by the cycleway.

The list includes the Australian Museum, Virgin Atlantic, Fitness Australia Ltd, Amanda Simons, Schenker, Westpac and Fairfax Media, the publisher of the Herald. These companies were not aware Mr Mahony had used their names. They have written to him demanding to be removed from the list.

The chief executive of the City of Sydney, Monica Barone, said "the alarm bells began ringing'' when she saw in the letter names of companies that had supported the cycleway.

Frank Howarth, the director of the Australian Museum, said Mr Mahony or his firm had never approached the museum.