A member of Defence confirmed to the joint standing committee for foreign affairs, defence and trade that in March this year, the pods on one of the amphibious assault ships suffered from leakage.
"We have had an issue this year in March where we had a small amount of leakage because one of the seals was leaking," a Defence spokesperson told the committee.
The vessel was undocked today and the seal will be replaced, the spokesperson said.
Confirmation of the leakage comes after both HMA Ships Adelaide and Canberra were in dry dock from March 2017 until June 2017 due to a migration of oils across seals in the LHDs' azimuth propulsion pod systems.
The docking and inspection of Adelaide in 2017 identified wear in some bearings in the port pod, which was assessed to be the likely cause of the oil contamination.
Defence Department Capability Acquisition and Sustainment Group (CASG) deputy secretary Kim Gillis told the Parliament’s joint committee of public accounts and audit last month that 45 per cent of the slippage of the LHDs related to fixing, and potentially recovering costs, of the propulsion pods for the LHDs, the Canberra and the Adelaide.
"We are in commercial negotiations so we have remediated the pods... we are in commercial negotiations with the companies and manufacturers, so you have an asset which is now operational, but we haven’t defined it as full operational capability until we actually (have) completed these commercial negotiations," Gillis said.
"This is something we are driving industry to make sure they have fully remediated and if there is an appropriate cost recovery … we are in commercial negotiations with those companies as we speak."
Last year, Defence confirmed the indicative costs of the unscheduled propulsion system investigations, repairs and servicing came to a combined total of $16.5 million for HMAS Adelaide and HMAS Canberra.
"The ability and extent to which the Commonwealth can access warranty and/or latent defect provisions is dependent on ongoing technical investigations and negotiations with industry," Defence said.
Negotiations with industry over the costs have been ongoing for some time, with Rear Admiral Adam Grunsell, AM, CSC, telling Senate estimates in October last year that Defence intends to recover some of the costs from industry.
The LHDs, which cost about $1 billion each, were designed and built by Spanish company Navantia with help from BAE Systems and German company Siemens.
Outgoing Chief of Navy Vice Admiral Tim Barrett told Senate estimates in October 2017 that Defence has "taken a cautious approach since" and the vessels will continue to be monitored over a period of time as they look at other issues during test and evaluation.
"There are other issues that we would seek to look through with the ship during this test and evaluation period to confirm that we have resolved all the issues we need to – noting that this is two years into a 30-year life," VADM Barrett said.
The Chief of Navy last year quashed rumours that Australia's operational intensity of the vessels is unsuitable for the ships, but added they are looking at its operations to ensure Defence's initial judgement on design and sustainment are suitable.
"We're looking at how that ship is operated and how we operate, to make sure that our initial judgements on design intent and sustainment practice are contemporary and appropriate to the way that we operate," VADM Barrett said.
"There's been no indication from the ship designer, in Navantia, as to how we're operating the ship. We do drive the ship differently from the Spanish Navy, from the armada, and, again, we are looking at that, but we are not – and it has not been indicated by the original equipment manufacturers that we are – operating outside the limits of what the equipment was designed to do.
"My biggest issue will be making sure we only use them at sea equivalent to the number of sea days that I'm funded to be able to provide them – and that is part of the sustainment issue. That is, if I've only got spares and maintenance to run them for a certain number of days a year and I'm asked to operate them beyond that, then I start ageing the platform far more quickly than we had intended and it wouldn't last 30 years."
The 27,000-tonne amphibious assault ships were commissioned on 28 November 2014 (Canberra) and 4 December 2015 (Adelaide).
The ships are able to land a force of over 1,000 personnel by helicopter and water craft.