Insurance company Tower will close its Christchurch office at the conclusion of its Canterbury Earthquake programme.

Tower chief executive Richard Harding said the number of remaining Canterbury earthquake claims continued to reduce with fewer than 300 open.

"The solid progress being made finalising claims means that we continue to move towards the finalisation of our Canterbury Earthquake recovery programme," Harding said.

"We have made the decision to communicate this now to provide clarity for our people."

"20 employees will be impacted by this decision and they will all receive full career transition support, including career coaching, training, as well as the opportunity to redeploy to our Auckland or Rotorua teams," he said.

The city was hit by a 7.1-magnitude earthquake in 2010 and a 6.3-magnitude quake in February 2011, in which 185 people died.

The Treasury in 2014 estimated the capital cost of the Canterbury earthquakes to be about $40 billion.

The NZX-listed company said it remained available to customers online at or on 0800 379 372 at any time.

Tower's shares are trading up 0.7 per cent at 68c.