Meanwhile, it has emerged that a balloon collided with the large Diamonds sculpture at the National Gallery in 2009.

It comes after yesterday's spectacular images of a balloon crashing into the side of the Treasury building.

Earlier today, Kingston photographer Daniel Keeffe was enjoying a balloon ride over Lake Burley Griffin at about 7.50am when he noticed a balloon that he thought looked to be in trouble.

"I looked down and slowly and slowly it got lower and lower," he said.

Mr Keeffe said the balloon hit the lake within metres of the shore at Yarralumla Bay, in front of the water police building, and stayed afloat on the water with the balloon inflated for about 15 minutes.

But Canberra Balloon Spectacular flight director John Wallington said it was common for balloon pilots to land on water.

Mr Wallington said spiky trees prevented the pilot from landing on the beach, so the pilot landed on the lake and waited for her support crew to arrive.

He said the pilot had 40 years of experience flying balloons, there were no commercial passengers in the basket, and she had remained sitting on the lake for only about five minutes.

A water police officer confirmed a balloon had landed on the water outside their lakeside building, but said the pilot had been in control of the situation and no assistance was required.