The federal health minister, Greg Hunt, has appealed to “everybody to stick with the facts” on Covid-19 after Facebook marked a recent post by a Liberal National party colleague as containing “false information”.

“Our view is very clear – that we set out the official medical advice, and we urge everybody to stick with the facts, to stick with the medical advice,” Hunt said in response to questions about the Queensland LNP senator Gerard Rennick.

Rennick’s Facebook output has included two posts over the past fortnight casting doubt over the accuracy of PCR tests, despite repeated appeals by state and territory leaders for anyone with Covid-19 symptoms to come forward and get tested.

As the federal government stepped up its appeals for Australians to be vaccinated as a pathway out of the pandemic, Rennick posted on 18 July an extract from an article describing an unnamed Covid-19 vaccine as “experimental gene therapy vaccine with plummeting efficacy”.

Facebook added a disclaimer that “Covid-19 vaccines go through many tests for safety and effectiveness and are then monitored closely”.

The same 18 July post questioned why Australia’s Therapeutic Goods Administration had not yet recommended use of ivermectin, a drug normally used against parasites such as worms and headlice.

Ivermectin has been promoted by rightwing figures worldwide for treating Covid-19, but a major study suggesting the treatment was effective against the virus was withdrawn last month due to “ethical concerns”.

In another post on 24 July, Rennick appeared to minimise the risk Covid-19 poses to younger people, attaching a graph with the age breakdown of deaths and writing: “You can’t protect the weak by destroying the strong.”

New South Wales health says there are currently 232 Covid-19 cases admitted to hospital, with 54 people in intensive care, 25 of whom require ventilation.

On Sunday the number in intensive care included seven people aged in their 20s, with Dr Jeremy McAnulty of NSW Health saying the figure “shows that the disease can be very serious in younger people as well is older people”.

On 26 July, Rennick wrote that it was “good to see there is a move towards a more accurate form of testing for Covid” in the United States, and posted a link to a purported news article about PCR testing that Facebook subsequently marked as “false information” based on a review by independent fact-checkers.

When asked on Monday about his LNP colleague’s Facebook posts, and whether he had counselled Rennick over the matter, Hunt said he had not seen all of the material.

“I’ve been aware of one of them in relation to ivermectin, and I provided the government information … and advice,” Hunt told reporters in Canberra.

The minister said in relation to the other posts, he would “go back and seek the original sources” before forming a view. Hunt then issued a broader appeal for politicians and the rest of the community to “stick with the facts”.

He said a record number of vaccinations had been administered over the past week, and urged “each Australian and every Australian to help contribute to protecting themselves and all others”.

“And if you’re in an older age group or you have friends and family in an older age group who haven’t been vaccinated, please encourage them to come forward – it can save their lives,” Hunt said.

Rennick has denied posting misleading material online. He edited one of the posts after the link to an article on PCR testing was marked as “false information”. He said the article in question had not directly asserted the PCR tests were inaccurate.

“I have said there is a move towards a more accurate form of testing,” Rennick said.

“Personally I think they are playing semantics here. You be the judge.”

Scott Morrison’s national opening-up plan, announced after Friday’s national cabinet meeting, says at the current time health authorities should minimise Covid-19 cases in the community through effective testing, trace and isolate capabilities.

Encouraging an increased uptake of vaccines is considered the key to moving to the next phases of the opening-up plan, in which lockdowns would become rarer.

In a bid to increase confidence in both the Pfizer and AstraZeneca vaccines, Australia’s acting health chief officer, Prof Michael Kidd, revealed on Sunday a breakdown of all recent Covid-19 cases acquired in New South Wales by vaccination status.

Kidd said of the more than 2,700 locally acquired cases of Covid-19 in NSW between 16 June and 28 July, 93% of those people had not yet been vaccinated, and 6% had been vaccinated with only one of the two doses.