It is estimated more than 500,000 Australians will have access to cheaper medicines when new products are added to the Pharmaceutical Benefits Scheme (PBS) on Tuesday.

Treatments for lung cancer, leukaemia, seizures or nerve pain, chemotherapy-induced nausea and high cholesterol levels will be listed on the PBS.

The new listings will see the price of the lung cancer medications come down from $11,400 per script, or more than $189,100 per course of treatment, to $40.30 per script and $6.50 for patients with a concession card.

For an average of 16 patients a year requiring acute lymphoblastic leukaemia treatment, the cost of a script will be reduced from about $44,500 per script, or more than $122,900 per course of treatment, to $40.30 per script.

"These are life saving drugs, they're also life changing drugs," Prime Minister Scott Morrison said.

Health Minister Greg Hunt said drugs to treat crippling chemotherapy-induced nausea would improve quality of life for more than 7,000 people.

"To give those patients the ability to have their treatments without the extreme nausea means more patients will continue through with their treatments and patients will have a better quality of life as they have those treatments," he said.

Medication to treat chemotherapy-induced nausea will be reduced from more than $80 per script.

"We are also reducing the price on 175 different medicines, savings of up to $390 million which will be across areas such as high cholesterol, or extreme pain and over 500,000 patients will benefit from them," Mr Hunt said.

Labor welcomed the listings but criticised the Government over a backlog of medications it claims should have been listed on the PBS months ago.

"They want the pat on the back for the listings, well I'm also going to be holding them to account for the non-listings," shadow health minister Chris Bowen said.

"There are around 60 drugs that have been recommended to the Government ... that remain languishing, unlisted.

"One of the drugs listed today was recommended six months ago."

The Australian Medical Association (AMA) also called for greater expediency.

"Obviously there are always going to be more drugs, more medications that need to be funded and brought back to the system, and so anything to expedite that process is a good thing," AMA president Dr Tony Bartone said.

The Coalition conceded there were delays but said they were due to companies building supply for the drugs.

"It's a bogus claim. It's an embarrassing claim from Mr Bowen," Mr Hunt said.

"We do it as quickly as the companies are willing to do it, we push them to be faster and we want them to be faster, but as soon as they're ready, we're ready."

"We will always list the medicines that the experts recommend."