The dual message is contained in letters the finance minister sent out Thursday to NDP Leader Tom Mulcair and the Liberal's Bob Rae for the 2013 budget, expected next March.
Flaherty tells the leaders and other opposition MPs and senators to write in their suggestions but not to bother proposing tax hikes of any kind, or costly, new spending initiatives.
He says higher taxes take money out of Canadian pockets, which would be counterproductive to creating jobs and economic growth.
He adds that additional spending could send Canada down the same disastrous path taken by many European countries.
The letter suggests the government would only consider minor adjustment to the plans he already has in place.
"It is in this spirit that I personally invite you to contribute your ideas as we begin to prepare Budget 2013 — especially cost-neutral or non-spending steps that the federal government might undertake to help support jobs and economic growth," he writes.
Flaherty recently began his cross-country budget consultations and will be in Victoria on Friday to hear submissions.
A spokesman says he also intends to meet with opposition finance critics, as he has in the past.
In the fall economic update released earlier this month, the government said in anticipates this year's deficit will be $26 billion and that it can achieve a balanced budget in 2016-17, or one year earlier if all goes to plan.