THE Wilderness Society has stepped up its campaign against potential financiers of Gunns Ltd's $2.2 billion pulp mill in Tasmania.  

Society pulp mill campaigner Paul Oosting said 15 major banks from around the world had committed in writing not to finance the proposed Tamar Valley pulp mill, The Mercury reports.

Banks previously rumoured to have been involved in backing the mill were among those who had committed not to finance the project.

Mr Oosting said the Wilderness Society and community campaigning organisation GetUp would seek to run an advertisement in the European edition of the Financial Times this week listing the names of banks that had declared they would not fund the mill.

The size of the advertisement would depend on donations.

The advertisement would also reveal the names of four banks -- Barclays Bank, Nordea, Macquarie Bank and JP Morgan Chase -- which would not comment to the Wilderness Society on their financing intention.

Banks that the Wilderness Society said had committed not to fund the mill are Deutsche Bank, Bank of China, Royal Bank of Scotland, Hypo Vereinsbank, Bank Austria, UBS, Erste Bank, Calyon, Banco Itau, Unicredit, Sumitomo Mitsui, National Australia Bank, Westpac, the Commonwealth Bank and ANZ.

A Gunns spokesman said the Wilderness Society's strategy was meaningless because there were a lot more than 15 banks in the world.

"They are fast running out of ideas to oppose the mill because it will be 100 per cent plantation-based within five years and will not use old-growth forests," the spokesman said.