The Liberal MP Warren Entsch has launched a crusade against single-use plastics as part of his new role as special envoy for the Great Barrier Reef.

Entsch told Guardian Australia he was inspired by the 10-year-old campaigner Molly Steer – who convinced Cairns to phase out single-use plastics – comparing her example favourably with activists who he accused of “frightening the living Jesus out of kids” to recruit school students to climate strikes.

Entsch said anti-Adani and Save the Reef activists had targeted his office for 18 months, accusing “the anti-fossil fuel brigade of throwing around a distorted and dishonest picture” of the reef’s health that has had a profoundly negative impact on the economy of his region.

“We don’t need to save the reef – it’s still going – we need to manage it and manage it well and we’re the best reef managers in the world,” he said.

Entsch represents the vast northern Queensland seat of Leichhardt, including Cairns, and has proved an influential backbencher – lobbying for the legislation of marriage equality in the Liberal party.

Entsch said a white picket cricket ground fence in Port Douglas made from recycled plastics inspired him to go to re-elected prime minister Scott Morrison on 20 May to ask for a role in reducing plastic waste. Morrison “loved the idea”, he said.

“I’m committed in my last term in government to develop a national policy on plastics, micro and nano plastics, to remove them from our beaches.”

The policy should cover use, recovery and conversion of plastics and include consideration of a ban on single-use plastics.

“I want to see single-use [plastics] out, but it’s much broader than that, and I’ll defer to experts on how we do it.”

Entsch said reducing plastic waste is an example of “solutions not slogans” that can make a practical difference to the environment.

Entsch suggested that student climate strikers had been “influenced by teachers, academics at university and activists” who presented “a distorted, one-sided” view of the reef’s health.

Entsch recounted his experience inviting a group of climate striking students to attend his office to get an alternative view point from a marine biologist and a tourist operator.

“What alarmed me when the kids came in – all they could do is talk in slogans: ‘save the reef’, ‘stop Adani’, ‘100% renewables by 2030’.

“One young girl was so distraught – she thought the reef would disappear in 10 years.

“These kids were well and truly brainwashed … that was disturbing to me.”

In 2017, Unesco opted not to list the reef as in danger after reviewing the government’s Reef 2050 plan, a decision it will reassess in 2020.

The Australian Institute of Marine Science reported in 2017-18 that trends in coral cover in the north, central and south reef showed steep decline that “has not been observed in the historical record”.

The coral reef scientist Prof Terry Hughes’s most recent paper found that the production of baby coral on the reef had fallen by 89% after the climate change-induced mass bleaching of 2016 and 2017.

Entsch suggested coral bleaching was primarily caused by warm currents from the northern hemisphere which Australia “can’t stop from coming down” and therefore needs to find “innovative ways to counter”.

“It’s the same for plastics – the bulk of it on our seas comes down from our northern neighbours. If we can create world’s best practice and get them to clean up their own backyard then we will reduce the volumes that come down to us.”

Entsch says education will be important to encourage people to “minimise the amount they throw out”. He will create a parliamentary friends of the Great Barrier Reef group, and has recruited Qantas, the Great Barrier Reef Foundation and the Great Barrier Reef Marine Park Authority.

Asked whether he will have input into the spending of $443m controversially given to the foundation in 2018, Entsch said he will express views but “leave it up to the scientists”.

“I am not interested in having a chequebook, I am interested in developing legislation.”

Entsch will work with Sussan Ley, the environment minister, and Trevor Evans, the assistant environment minister, who were also appointed in Sunday’s reshuffle.