Asciano will axe 270 jobs after completing a $348 million expansion of its container terminal at Port Botany in Sydney.

Asciano on Wednesday said the expansion project would increase capacity at the port from 1.15 million to 1.6 million TEU (20 foot equivalent units) per annum to meet current trade growth forecasts.

But, once the project is complete in mid 2014, Asciano will make about 270 jobs at the port redundant.

"We will be going above and beyond to invest significantly in, and support, our employees throughout the transition period," chief executive John Mullen said.

Mr Mullen said employees affected by the job cuts would also be provided with employee assistance and support programs including training, financial planning and career transition assistance.

"All of our employees will also have access to additional incentive payments conditional upon maintaining appropriate levels of performance," he said.