Confectionery firm MasterFoods Australia New Zealand is giving away free chocolate bars in Sydney in a bid to recover from a massive recall prompted by contamination threats.

The company was forced to remove its Mars and Snickers bars from supermarket shelves in New South Wales in July after an extortionist claimed to have put seven contaminated Mars and Snickers bars in retail outlets in Sydney. The demands made by the extortionist were directed at Sydney's Star City Casino, and MasterFoods said it was randomly drawn into a conflict between the extortionist and the casino over which it had no control.

Thousands of bars were given away in Sydney on Sunday; more than 100,000 bars will be given away in total as part of the relaunch.

"These are the first of the three million bars that we have produced to replace those we destroyed," said Andy Weston-Webb, president of MasterFoods Australia New Zealand.

The official relaunch will be on 18 August, although the first bars will be delivered to major retail stores this week. During the course of the next few weeks, they will be returned to sale in more than 40,000 outlets across NSW.

"We have had no contact from the extortionist for a month. Together with the police we believe that this passage of time has diminished the risk," said Weston-Webb. 

"The Police and the NSW Food Authority support our decision to go back on shelf at this time," he added. The fresh bars will be distinguishable from the old ones, as they will not have the green 'Bid 4 It' promotional flash that the old bars carried.