The value of Tasmanian merchandise exports to China, including Hong Kong, increased by 20.5 per cent ($282 million) in the year to March, according to state Treasury analysis of Australian Bureau of Statistics figures.

"The primary driver was an increase in metallic ores and metal scraps, as well as non-ferrous metals," Treasury said.

China accounted for 42 per cent of the value of Tasmanian merchandise sent overseas during the year, and Hong Kong a further 2.8 per cent.

South Korea (7.2 per cent) was the next biggest export market, followed by the US (6.5 per cent and up by 11.2 per cent) and Taiwan and Japan (both 6.2 per cent).

The overall value of overseas merchandise exports increased by 3.2 per cent compared with the previous year to $3.7 billion.

That was within sight of record levels, which peaked in November 2018.

Trade Minister Jeremy Rockliff said the 3.2 per cent increase was the third highest annual export growth rate in the nation and "demonstrates Tasmania has what the world wants".

"We have a clear plan to diversify and expand our exports ..."

He said the state government's Tasmanian Trade Strategy and annual action plans "give business and industry the direction and confidence to grow exports, driving economies across regional Tasmania and creating jobs".

The mining and metals industries accounted for easily more than half of the value of Tasmania's overseas merchandise exports during the year.

That included non-ferrous metals (34.1 per cent of total value) and metallic ores and metal scraps (23.5 per cent).

The value of metallic ores and metal scraps exports increased by 28.3 per cent during the year.

"Other and confidential" was the third most lucrative export category (19.7 per cent).

The value of seafood exports climbed by 4.2 per cent.

They provided 7.4 per cent of total overseas export value, as did meat exports,

Dairy products (4.2 per cent) and fruit and vegetables (2.2 per cent) followed.