The Kotowaka Maru arrived at ConocoPhillip's Wickham Point plant in Darwin early last Wednesday to load the first cargo from Australia's second LNG export project.

The long-awaited shipment was due to leave Darwin within two days, but the 125,000 cubic metre carrier still remained in the port last night.

Conoco Phillips has released a statement saying the gas plant commissioning is "experiencing issues".

The company said such delays were common in the commissioning stage of projects.

"There was an expectation that it would leave on the weekend, but during the commissioning process you get these issues and the ship will leave when it's ready to leave,” a ConocoPhillips spokesman told The Australian newspaper.

"We are loading the vessel, but we are loading it at a reduced rate. Generally, the first time you expect it to take longer because you are having to process a number of issues."

The delay of the shipment was also seized upon by the Maritime Union of Australia. "This will completely tarnish Australia's international reputation as a reliable supplier of LNG," said MUA national organiser Mick Killick.

But ConocoPhillips spokesman said the shipment was actually ahead of its original schedule. The contract is not due to start until March and during the commissioning stage the company is planning to sell severla cargoes on the international LNG spot market.

About 3 million tonnes of LNG, drawn from the Bayu Undan gas fields in the Timor Sea’s Joint Petroleum Development Area, have been contracted each year to Tokyo Electric and Tokyo Gas for 17 years.

LNG gas carriers are due to arrive in Darwin every seven to 10 days, with each load initially expected to take 10-12 hours.