Independent MP Andrew Wilkie's grip on his Tasmanian seat of Denison has tightened with the Liberal party confirming it will direct preferences to him.
Liberal state director Sam McQuestin says the party remains determined to win the marginal seat on September 7, but Mr Wilkie represents "the best of a bad bunch" among its rivals.
The ALP held the seat for 23 years before Mr Wilkie's win in 2010 and Liberal candidate Tanya Denison is considered only an outside chance of taking it.
But with Ms Denison listed first on the ballot paper, her preferences will be crucial in a seat Mr Wilkie holds over Labor by just 1.2 per cent after he leapfrogged from third place.
"The Liberals are determined to win Denison in order to deliver growth and jobs, and we have a fantastic candidate to do so in Tanya Denison," Mr McQuestin said in a statement.
"(However) we need to give guidance to Liberal voters about the other candidates.
"As far as the Liberals are concerned, it's Tanya Denison first, daylight second, and then Mr Wilkie as the best of a bad bunch."
The high profile independent was already favoured to retain the Hobart-based seat, with the ALP's Jane Austin his main challenger.
Labor went on the attack at the announcement but Mr Wilkie repeated a guarantee he had not entered any preference deals.
"The Liberal party decision is entirely their own work and does not indicate any allegiance on my part to that party," he said.
"In fact at the 2010 election the Liberal party also directed preferences to me but after that election I supported the Labor Party to form government."
The ALP has attempted to portray a vote for Mr Wilkie as a vote for Tony Abbott, running billboard advertising around Hobart with a photo of the pair shaking hands.
Mr Wilkie has complained to Prime Minister Kevin Rudd about the advertising, and ruled out supporting any party after the election.
But Labor's Ms Austin said Denison voters should be asking why the Liberals will preference Mr Wilkie.
"There is too much at stake for Denison in this election to risk Tony Abbott or Andrew Wilkie," she said.
Greens senator Peter Whish-Wilson said his party was likely determine who it will preference in Denison in the next week.
"Obviously it's going to reduce (Greens candidate) Anna Reynolds' chances but if people vote according to their own preferences ... then they will make their decision," he said.
