Premier Lara Giddings announced the incentive package yesterday, which also includes a $20 million loan, but admitted no companies were keen to invest right now.

"In the last few years several major international silicon producers have visited the state to explore the possibility of establishing a world scale silicon smelter in Tasmania," Ms Giddings said.

Talks with an unnamed German company in 2009 came to nothing.

Tasmanian Minerals and Energy Council chairman Wayne Bold said the drop in the Australian dollar since then made it a more viable option.

"The greatest interest in this sort of product is in Europe at the moment but don't ever underestimate the Chinese interest, it grows very quickly," Mr Bold said.

The election promise is part of the party's resources policy, which will be released later this week.

The announcement follows news that the government is considering a request from Shree Minerals to defer collection of royalties from its new iron ore mine at Nelson Bay.

The Liberal Party and Greens attacked the silica smelter incentive scheme.

Liberal resources spokesman Adam Brooks labelled it a sham.

"We can expect to see more of these fake policies which sound grandiose but can't be delivered," Mr Brooks said.

Greens leader Nick McKim said it was more corporate welfare.