Workers with Capital Weed Control were spraying undergrowth beside Ginninderra Creek on May 20, 2008, when they noticed nearby poplar trees had been vandalised, apparently with a tomahawk.

The foreman of the team, contracted by the ACT government, feared the trees might fall and called his director, who told him to leave the area and work further along the creek.

The company's director then claimed to have called a government representative from Parks, Conservation and Lands.

He claimed the public servant who managed the contract and was the ''field supervisor'' came to the site and advised the area was safe.

But the ACT Supreme Court found that later that day a 15-metre tree fell without warning on Capital Weed Control worker Gerald Brennan, injuring him severely.

Mr Brennan put in a claim against his employer, which was settled.

But the company then took the ACT government to the Supreme Court, claiming it should contribute to the compensation because of the public servant's advice that the area was safe.

Master David Harper rejected the argument, finding that there was no breach of any duty of care between the ''relatively junior ACT public servant'' and Capital Weed Control.

Master Harper found it had not been made clear to the government representative that her advice was being relied on to make a decision on sending the employees back to work.

He ruled there was nothing to make her ''aware that she was in any way taking responsibility for the safety of the defendant's employees on the site''.

The company took that decision to the ACT Court of Appeal but it was dismissed in November and the court's reasons were published on Thursday.

Capital Weed Control had argued the government representative was asked to inspect the area in her capacity as field supervisor and contract manager, and that she had a background in horticulture and had assumed the role in advising on the safety of the vandalised trees.

The ACT government argued Master Harper should never have found its worker attended the site on the morning of the accident or advised workers it was safe to continue.

The ACT Court of Appeal dismissed the company's arguments, finding there was not sufficient evidence to show the public servant had breached a duty of care by providing the advice that it was safe to proceed. It found the company's director could not have believed the woman possessed the right experience and expertise to advise them that the tree would not fall.

The court noted that Capital Weed Control had failed to prove the tree had fallen because it was vandalised, or that a qualified tree inspector would have given different advice.

Capital Weed Control was ordered to pay costs when the judgment was handed down in November.