UPDATED 7.10AM: Those fighting for Pharmac to fund the anti-cancer drug Keytruda will take their fight to parliament today.

LISTEN ABOVE: Chris Jackson of the Cancer Society Speaks to Rachel Smalley

A petition is set to be presented to parliament at around midday calling for the government to increase Pharmac's funding so it can make the drug available to melanoma patients.

But Prime Minister John Key said he's leaving the ball firmly in Pharmac's court when it comes to funding the drug.

Key said that as far as he knows, there's no movement on funding the drug, but Pharmac is always looking at which drugs it should fund in which order, and the government is also going through its Budget round.

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"I'm not going to rule out that it gets funded in the future, at the moment that's in the hands of Pharmac to decide on an efficacy basis which drugs it thinks it should fund and which ones it doesn't," Key said.

Pharmac has previously said it will keep funding for Keytruda under review but late last year ruled out funding it for patients with advanced metastatic melanoma.

The drug funding agency has said more is needed to be known about the drug's long term effectiveness and patient survivability.

However, Melanoma New Zealand's Rosalie Fisher says action is needed, and quickly.

"While this is petition is about one particular drug, I think it represents the need for a number of drugs to be fast-tracked rapidly for patients with melanoma," she said.

Fisher notes that Keytruda doesn't help all patients, but it is suitable for a substantial portion of melanoma sufferers.