Henry Rolland Park will feature fitness equipment, a 150 metre lakeside boardwalk, picnic and barbecue facilities and lawn areas.

From 10am to 4pm on Saturday, the Commonwealth Avenue park will also be home to live music, fitness classes, games and children's activities.

Food and drink vendors will be onsite for the opening celebrations. Lakeside business Go Boats will run short trips around West Basin for a gold coin donation and Canberra Urban Adventures will run their kayak and bike hire services from the park.

Descendants of Henry Rolland - an architect who supervised construction of parts of early Canberra - will attend the open day.

The project was slightly delayed and over the original budget of $10 million. City Renewal Authority chief executive Malcolm Snow said the park was "a challenging, complex project".

"Once you start doing anything near water, building the concrete boardwalk, it’s always challenging, and in the middle of it a very wet period," he said.

"As often happens with these large civil works that require work in water there’s always inevitably going to be some delays.

"I think it was important that we get it right and coinciding with school holidays we’ll have the maximum opportunities for as many people to come down and experience the new park."

The opening of Henry Rolland Park will mean parts of the lake circuit will be reopened to cyclists, joggers and walkers. Mr Snow said car access would remain under the bridge between Commonwealth Avenue and Commonwealth Park "in the short term".

The design of stage two of the West Basin project has started with plans for an extension of the concrete boardwalk around Lake Burley Griffin's edge.

Negotiations with the Commonwealth continue on the reclamation of the lake bed, Mr Snow said.