Tasmanian merchandise exports sent overseas were worth $3.655 billion in the year to the end of September, going by Australian Bureau of Statistics figures.

That was down by about $10 million per month compared to the average from the previous year.

Above average sales to China in August and September ($107 million and $116 million respectively) could not avert the recent decline.

Even so, export sales values remained near historic highs.

Other bigger export totals in September included:

The ABS estimated Tasmania sent $293 million worth of goods overseas in September, with $273 million worth of those going to APEC (Asia-Pacific Economic Cooperation) countries.

Just $3 million worth went to EU countries.

State Treasury analysis of the export figures to the end of August showed export value had declined slightly in recent months on a 12-month average basis following a strong growth spurt from early 2017 until late 2018.

Mainland China accounted for 32 per cent of Tasmanian merchandise exports during the year.

Non-ferrous metals ($1.476 billion) accounted for 39 per cent of export value.

"Other and confidential" was the second strongest category ($821 million), followed by metallic ores and metal scraps ($591 million).

Seafood, meat, dairy products, paper and paperboard, fruit and vegetables and vehicles including vessels followed in that order.

The export value of dairy products increased by 40.7 per cent for the year, with vehicles including vessels up by 80.7 per cent.

Their growth rates were easily the strongest.