Prime Minister Scott Morrison has implored families of aged care residents not to be anxious amid reports of vaccines being delayed and a bungle that saw two elderly people given incorrect doses.

It has now emerged that about 150 doses of Pfizer’s COVID-19 vaccine had to be thrown out after a possible storage error at a nursing home in Melbourne.

The vaccines were delivered to the St Vincent’s aged care facility in Werribee on Wednesday and administered by Aspen Medical.

The company has advised the government that 25 vials were left over and stored in a fridge.

But the company was not able to confirm the precise temperature at which the vials were stored and so a decision has been taken to dispose of the vials

Speaking before the Werribee incident was confirmed, Morrison said logistical issues in the early phase of the rollout would be addressed quickly.

“I’m absolutely confident that as we go from day to day, the lessons of each day will only make the system better,” he told reporters in Sydney on Friday.

“At all times, safety is the paramount issue.”

Vaccinations are complete at about 90 aged care homes, with another 20 expected to be done on Friday.

Some 23,000 Australians have been vaccinated so far, including frontline healthcare workers and hotel quarantine staff.

The rollout has not occurred as quickly as the federal government promised.

Healthcare Australia – which has the federal government contract for the vaccination workforce in NSW and Queensland – has scaled back and slowed down their processes.

The company is in hot water with the government after two elderly nursing home residents in Brisbane were given too much of the vaccine by a doctor who had not completed mandatory jab training.

The 88-year-old and 94-year-old patients have shown no signs of adverse reactions.

Health Minister Greg Hunt says vaccinations at other nursing homes were pushed back as a result.

“Unfortunately, they notified people by email, 10.45 at night,” he told 2GB radio.

Healthcare Australia is on notice its contract could be torn up if there are any more major problems.

Sonic Healthcare is now helping with the residential aged care vaccine rollout in Queensland and NSW.

Aspen Medical has the federal contract for the vaccination workforce in all other states and territories.

Therapeutic Goods Administration head John Skerritt says an investigation is looking into what happened with the 25 vials in Victoria.

“It’s something that the team is looking at, whether there has been what we call a breach of cold chain,” Professor Skerritt told ABC radio.

The Pfizer vaccine has six doses per vial and is stored at minus 70 degrees Celsius.

Logistics company DHL is transporting the doses across the country in portable freezers.

Morrison flagged Pfizer was looking at changes to the vaccine’s storage temperature, which is being considered by the TGA.

Victoria will soon ease mask rules and social gathering restrictions despite recording two new locally acquired cases of coronavirus.

State health authorities confirmed the two cases are close contacts of pre-existing cases and have been in quarantine during their infectious period.

South Australia has lifted the last of its travel restrictions, clearing the way for people from Melbourne to enter the state from Friday with quarantine or testing.

Queensland will also reopen to Melbourne from 1am on Saturday.