The old ACT Legislative Assembly foes are stuck together for another three years after both being returned to the senate.

The Labor and Liberal senators were officially declared the winners of the ACT's two senate seats at Old Parliament House on Tuesday, following a long and vitriolic election campaign.

They said their priority now was working for the benefit of the ACT.

"We've got a history, we go back a few years but I think we both take our responsibilities to represent Canberra very seriously," Senator Gallagher said.

Senator Seselja said: "There are some things we come together on and obviously we disagree on a lot, but there are some things where we can agree and there's no doubt we both love Canberra and where we can get better outcomes for Canberra we're happy to work together."

Both the Liberal and Labor parties recorded a positive swing when Canberrans headed to the polls last month, which appears to have paid dividends for the local senators.

Senator Seselja became the first Canberra Liberal promoted onto the front bench when was named the new assistant minister for social services and multicultural affairs while Senator Gallagher has picked up the shadow portfolio for small business and financial services.

"We were very confident when we saw the numbers coming in on the night and it's great to see it reflected in the swing toward us, given nationally we didn't so obviously that's encouraging and hopefully it's a reflection of three years of local engagement and hard work," Senator Seselja said.

Senator Gallagher, who quit as Chief Minister in 2014 to run for the senate spot vacated by retiring ACT Labor Senator Kate Lundy, said it was a "great honour" to be elected in her "own name".

"At the end of the day for me it's going to be about responding to what's in the best interest of Canberra for every single issue and working that through my party room along with Gai [Brodtmann] and Andrew [Leigh] as well," Senator Gallagher said.

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