Coles is launching a new collectible promotion of plastic toys on Wednesday, while the vestiges of the supermarket giant’s last campaign are still having a negative impact on the environment.

From this week, shoppers can collect one of 24 plastic fruit or vegetable toys for every $30 they spend in-store as part of the Coles Stikeez campaign.

Endorsed by the Healthy Kids Association, the campaign is promoted as a way to encourage Australians to eat more fruit and vegetables and “make healthy eating fun for the whole family”.

It follows last year’s Little Shop promotion, which had shoppers collecting 30 miniature, mostly plastic versions of well-known household items including mini bananas, household bleach and bottled water.

Little Shop was considered a marketing success, helping to lift Coles sales by 5% in the first quarter of 2019. At the peak of the promotion, customers were selling complete sets online for up to $1,000, while “rare” items like the mini red hand sold for $250.

There was extensive criticism of the campaign at the time, particularly as it was launched after Coles banned plastic bags. The environmental engineer, Laura Trotta, described the campaign as an “environmental nightmare”.

“I think it really destroys their credibility in that sense. They are asking us to see them as responsible corporate citizens yet they just roll out heaps of cheap plastic products for free, and most of them end up in landfill.”

The latest Coles campaign Stikeez with 24 fruit and vegetable toys to collect. Photograph: Coles

Customers quickly tired of the plastic toys. Distinctive Options, a not-for-profit disability support organisation that collected unwanted Little Shop toys to use as communication aids for individuals and programs, were inundated with toys.

Chief executive Ernie Metcalf said they received “thousands” of toys not long after the promotion began. Only two months later they put up a post on Facebook asking supporters to stop sending them.

The heady days of high-priced collectables changing hands online soon died down. These days complete sets are available for just $50.

However, the promotion continues to have an environmental impact. According to Tangaroa Blue Foundation, the charity that collects data on beach cleanups, more than 35,000 items categorised as toys and other were collected in 2018, around 7,000 more than the previous year.

Two Little Shop toys were picked up by Tangaroa Blue last year: one at Belmore Basin, Wollongong Harbour and a Little Shop miniature nappy packet toy was found at Port Campbell Bay. A spokesperson noted there could have been more as items could have been logged without descriptions.

In November a miniature Little Shop Nutella toy was found on a Bali beach, by the Brisbane-based veterinarian Dr Stephanie Shaw. Although it was likely to have been transported by an Australian rather than washed up on the beach, Shaw told Caters News that the toy could be deadly if swallowed by a turtle or sea bird.

Environmental groups have slammed the latest promotion. Jayne Paramor, the deputy director of environmental waste campaigners Boomerang Alliance, said Coles hadn’t learnt from the Little Shop criticism.

“[Coles] have again placed profits ahead of sustainability, using these so-called ‘collectables’ to bring consumers into their stores, with no regard for the environmental impact that this plastic tat will have as it heads for landfill.

“The fact that they have moved on to a new promotion just six months after the Little Shop was launched shows the lack of longevity that these promotions really have. Rather than expanding on the previous campaign, which might have kept the Little Shop items out of the bin for longer, consumers are encouraged to ditch the last lot, which are now ‘old hat’ and move on to the new sets.”

The Greens spokesman Justin Field said: “Coles may have considered their ‘Little Shop’ promotion a business success but any financial benefit for Coles comes at the social and environment cost of a legacy of plastic waste. These plastic items will find their way into creeks and the ocean injuring marine life, or will sit for thousands of years in landfill after they are inevitably thrown out.”