"I also get to talk to the other staff who are here for coffee. You learn a lot in the coffee queue about what's really going on," he said, with a laugh.

The $3.1 million cafe and extension has recently opened, taking advantage of the museum's location on the Acton Peninsula by jutting the new section out towards Lake Burley Griffin.

"We now have this unique view on the lake," Mr Sayers said.

"I think what's happening in Canberra is we're suddenly getting a whole lot of different viewpoints on the city. This is one of them, the arboretum is another."

The original architects, Ashton Raggatt McDougall, were commissioned to do the work, not least to clear the main hall of tables and chairs and the remnants of the old cafe and create space to show the big exhibits previously in storage in Mitchell.

A separate extension for staff administration is still underway and not expected to be completed until June.

Mr Sayers said next step would likely be a revamping of the internal galleries so that visitors had a more "coherent" experience of the museum. Most of the galleries were now 12 years old and in need of a re-jig.

"I think that the museum has from day one been a challenge for people in terms of the coherence of the experience," Mr Sayers said.

"You sort of go from one thing to another and it can sometimes be quite challenging in terms of 'I'm not quite sure how that relates to that'."

He hoped any revamp would give visitors a "a greater sense they've been on a journey" when they came to the museum.