Ms Seales died on Friday morning, shortly after learning that a judge ruled her doctor could not help her end her life without risk of prosecution.
Her campaign and trial reignited calls for a national debate on the right to die for terminally ill people.
John Key said this morning MPs would have to treat any proposed euthanasia law as "a conscience issue" but it was inevitable the topic would re-emerge in Parliament.
"I personally would probably support legislation aimed in the way Lecretia wanted it," Mr Key said on TV One's Breakfast this morning.
He said everyone had a "slightly different view" on the possible wording or interpretation of euthanasia laws but he expected several MPs to propose bills and he did not believe the Government needed to put the topic on its agenda.
"It will eventually get debated again."
Justice David Collins released his judgment to the public on Friday. It rejected Ms Seales' bid and said only Parliament could give her what she wanted.
"The complex legal, philosophical, moral and clinical issues raised by Ms Seales' proceedings can only be addressed by Parliament passing legislation to amend the effect of the Crimes Act," the judge said.
