Campaigning in the marginal Victorian seat of Corangamite on Wednesday, Mr Morrison said Josh Frydenberg would remain as treasurer while Marise Payne, Peter Dutton and Mathias Cormann would also stay in their portfolios of foreign affairs, home affairs and finance.

Mr Morrison challenged Labor leader Bill Shorten to name his home affairs minister, an issue that has been dogging Mr Shorten for several months.

The PM said home affairs, defence, treasury, finance and foreign affairs were "the critical portfolios that sit at the central agencies of government".

"What Australians need to know is in the key portfolios."

Mr Morrison said Education Minister Dan Tehan and Health Minister Greg Hunt would also stay in their portfolios if the government is re-elected.

Mr Morrison will be without an incumbent Jobs and Womens' Minister after Kelly O'Dwyer announced her retirement in January. Indigenous Affairs Minister Nigel Scullion will also leave politics on May 18.

Mr Morrison could not say who would take on the Indigenous Affairs portfolio, despite saying Indigenous youth suicide was an issue he wanted to focus on after Saturday.

"The thing that focuses my mind most, when it comes to Indigenous issues, is I want young girls to stop killing themselves in regional, remote communities," Mr Morrison said.

"I can't tell you a more important Indigenous policy issue than that. It grieves my soul that young girls are killing themselves in remote Indigenous communities and I will do everything I can to stop that."

Jobs and Industrial Relations will also be key portfolios with wages a key issue for Labor during the campaign.

Mr Morrison accused Labor of shirking its national security obligations by failing to name who would take on the Home Affairs portfolio amid rising international tensions between the US and China.

"I think [it's] an abrogation," Mr Morrison said. "It is bad enough that Labor's record on border protection is as woeful and as appalling as it is but to go to this election on Saturday and not even tell Australians who's responsible for keeping the boats stopped on Sunday?"

Labor leader Bill Shorten has repeatedly refused to name a potential Home Affairs minister or detail how he would structure the portfolio.

Mr Morrison spent Wednesday morning campaigning in the crucial marginal seat of Corangamite.

Mr Morrison said he "made no apologies" for the government's spending in the electorate. The seat has attracted over $26,000 per person in election promises, with $3.1 billion being spent on infrastructure, defence and community grants - more than any other electorate.