Chris Steel will be the new Transport Minister while Rachel Stephen-Smith will take on the health portfolio, following Labor frontbencher Meegan Fitzharris' shock resignation.
And while Ms Fitzharris' expected replacement Deepak-Raj Gupta was previously unaligned, Chief Minister Andrew Barr says he will join the right faction.
His announcement came just hours after Ms Fitzharris revealed she would be leaving politics in the coming weeks and stepping down as a minister on July 1.
Mr Barr said an additional new minister would likely be announced in the coming months, with Mr Steel and Ms Stephen-Smith keeping all their existing portfolios, on top of their new ones, until then.
Mr Steel is the current current City Services Minister and a relatively new member of cabinet, having been elevated last year.
He will take on the role of Transport Minister.
Minister Rachel Stephen-Smith - whose current portfolios include disability, children, youth and families, and Aboriginal and Torres Strait Islander affairs - will become Health Minister.
Mr Barr said a further reshuffle was expected in the coming months, but Mr Steel and Ms Stephen-Smith would retain transport and health respectively.
He said they were chosen for their experience and the alignment with their existing portfolios.
He said he did not believe Ms Fitzharris' workload, who was in charge of two high profile portfolios, was related to her decision to depart politics.
"Every ACT Minister through the history of self government has had multiple portfolios and they were the ones Meegan wanted.
"If at any point any minster says 'I simply have too much on my plate' then of course we will respond to that as best we can, but ... like Tasmania and the NT, where you're going to have a cabinet of seven, eight or nine each minister's going to have somewhere between four and six portfolios.
"At one point early in my career ... I had eight or nine portfolios."
Ms Fitzharris is expected to be replaced by Deepak-Raj Gupta in the Yerrabi electorate, who on Wednesday said he would accept the position.
Mr Gupta, 52, is a leader in the Indian community in Gungahlin and a public servant. As recently as midday, Mr Gupta said he was factionally unaligned in the Labor Party, but Mr Barr on Wednesday revealed he would join the right.
Mr Barr is a member of the right, as is Ms Fitzharris, so the move will ensure the factional makeup of Labor MLAs remains the same, instead of weighing heavily in the left's favour.
"I've known Deepak for a long time and he's a strong personal supporter and he will join parliamentary centre coalition," Mr Barr said.
"There will be a like for like situation."