A fall in mining export volumes has blown out the trade deficit to $3.3 billion in October.
It was larger than the $2.6 billion deficit economists were expecting and larger than the September deficit of $2.4 billion.
Exports fell three per cent in the month, while imports were flat, the Australian Bureau of Statistics said on Thursday.
JP Morgan economist Tom Kennedy described the result as soft result and said he was surprised by the fall in export shipments.
"Non-rural goods, which include most of Australia's main export commodities such as iron ore, fell commensurate with the headline figure, and was the main catalyst behind today's disappointment," he said.
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"That said, Australia's other key export categories, rural goods, and services, also were a touch softer than expected."
Mr Kennedy said there were no surprises in imports, with values holding steady during the month.
Exports, particularly in mining and resources, have been crucial for economic growth in 2015.
NAB economist Tapas Strickland said most of the deterioration in the trade deficit was in iron ore export volumes, which was particularly evident in declining iron ore shipments in Port Hedland.
"There is a risk that even with iron ore exports expecting to bounce on the back of the Roy Hill mine commencing exports soon, a lower iron ore price will likely weigh on the value of iron ore exports in the quarters ahead," he said.
However Mr Strickland is confident the trade deficit will shrink in the new year as liquefied natural gas (LNG) exports grow significantly.
"The Santos-led GLNG had its first export of LNG in mid-October, and Origin-led APLNG is expected to commence first export shipments soon," he said.
"More growth from LNG is expected in 2016 and 2017 from these and other LNG plants such as the giant Gorgon LNG facility."
A large fall in mining export volumes was the key factor why the economy grew at a sluggish 0.3 per cent pace in the June quarter.
In the following three months, net exports bounced back and contributed 1.5 percentage points to September quarter economic growth, which came in a 0.8 per cent.
