The coalition will throw money at roads and Labor is focusing on mental health as their leaders both officially launched the Braddon byelection campaign with personal digs at each other.
Cash promises and well-worn jokes were a staple of the near simultaneous launches on Sunday.
"The choice is very clear," prime minister Malcolm Turnbull told supporters in Burnie.
"The only candidate in the Braddon by-election who can be part of a government to deliver after election day on 28 July is Brett Whiteley."
The coalition pledged $60 million in funding towards the Bass Highway, with a further $10 million in upgrades for the Murchison Highway.
Mr Turnbull also attacked "Labor lies" that claimed a coalition government meant cuts to health and education.
He said government funding for Tasmanian hospitals had increased by 42 per cent since Labor lost office in 2013.
"(Labor leader) Bill Shorten, in particular, believes that if you repeat a lie often enough, people will believe it," Mr Turnbull said.
Mr Shorten, who was also on the hustings in Devonport accused the prime minister of engaging "in one of his personal tirades against me".
"If he really wants my job as opposition leader, he can have it."
The opposition pledged to create a new Burnie headspace centre to deliver greater early intervention mental health services for young people.
It will also move to improve access to Centrelink services, by adding an extra 50 staff in Burnie and Devonport centres.
"A vote for (Labor candidate Justine Keay) isn't just a vote for better health services, tangible health services on the ground," Mr Shorten said.
"It's a vote to back local jobs, to back local business."
A June ReachTEL poll found the coalition leading Labor at 54-to-46 per cent in the northwest Tasmanian electorate.
The by-election is one of five on July 28, with most sparked by the resignation of sitting MPs caught up as dual-citizens, including Ms Keay.
