Independent senator Steve Martin joins the Nationals Party in boost for Coalition

The Turnbull Government has boosted its numbers in the Senate, with Independent Tasmanian, Steve Martin, joining the National Party.

Senator Martin announced the move with Deputy Prime Minister and Nationals Leader, Michael McCormack, in his hometown Devonport.

The former Mayor becomes the only National representing the Apple Isle.

Senator Martin, who entered the senate as part of Jacqui Lambie's party, said he supported the Nationals' commitment to rural and regional Australia and support for small business.

It means the Coalition will have 31 Senators, and will now only need eight crossbenchers to get its legislation through the Upper House.

Senator Martin had already backed the government's tax cuts for big corporations.

Mr McCormack made an unfortunate comparison, describing his new recruit as a Tasmanian Tiger who'll fight for the state's interests.

The leader said Senator Martin's business background made him a "natural fit" to join the Coalition.