OTTAWA -- The Conservatives and NDP have spent the first month of the campaign adding only a handful of big ticket spending items to the list they unfurled months before the official election call.

And number-crunching by The Canadian Press shows they don't have the fiscal space to announce much more.

A review of spending promises to date shows that of the big three parties, the NDP has promised about $2.7 billion in gross spending and tax cuts for the next fiscal year. Net spending so far is about $609 million when taking into account the NDP plan to eliminate the doubling of tax free savings accounts contributions and income splitting for families, but not for seniors.

The Conservatives have only promised about $570 million for the 2016-17 fiscal year, the first year for which the winner of the Oct. 19 vote will get to set a budget.

The Liberals have promised more than $8.6 billion in net new spending next year -- far more than their opponents combined.

One political observer said the numbers suggest the rest of the campaign could be one where Canadians are treated to only a few big-ticket spending or tax promises.

"In this sort of air of the permanent campaign, they've decided -- all of them -- to put out pretty major planks even prior to this campaign getting going," said David McGrane from the University of Saskatchewan. "The campaign period itself becomes a bit more about reinforcing your brand using these announcements you already made as opposed to making new announcements."

The Conservatives announced smaller measures -- only one promise tops the $1 billion mark -- that have yet to push them into deficit territory, if Parliamentary Budget Officer projections are used as a base.

In the next fiscal year, the Conservatives are tracking to have a $30 million surplus after promising away almost all of the $600 million surplus the PBO projected last month.

The $30-million figure, however, provides a slim margin of error given slumping oil prices and a technical recession during the first half of the year -- two issues the PBO said could further erode the projected surplus in each of the next two fiscal years. The Tories have yet to identify any new revenue streams that could pay for big spending lines still to come, such as defence, McGrane said.

McGrane said it's also tough to see any big new spending items from the Tory camp because some of the biggest pledges -- increasing the monthly universal child care benefit payment and income-splitting -- were implemented before the election campaign began.

The Liberals have the same problem, he said. The party has committed billions in infrastructure spending, a new child care benefit of their own to replace the Conservative plan, First Nations funding and care for veterans, leaving many to wonder what else they could have up their sleeve that could be bigger, McGrane said.

McGrane said the party was playing "transactional politics" with their spending promises, hoping the spending will be more important to voters than the deficits they plan to run. He said the party may be trying to get back in the game as polls have suggested they are running third in a tight three-way race.

The NDP's numbers suggest that without any new revenue in the first year of a mandate, the party would run a tiny deficit of $9 million, not including proposed increases to funding to the CBC. The NDP, however, has two big promises left to be made public: how much they intend to raise corporate tax rates, and how quickly they intend to roll back government subsidies to the oil and gas sector, both of which could help the party keep its pledge to balance the books in its first year.

A one per cent increase in the general corporate tax rate could raise about $1.9 billion, according to the Parliamentary Budget Officer, while cutting subsidies could save millions more. The details of their spending plans also show the party is planning to ramp up spending over several years, or top up existing spending to get to the big figures touted on the campaign trail.

The tactic is part of the NDP's DNA, McGrane said.

"The NDP brand ends up looking like a party ready to govern, a party that is responsible, as opposed to a sort of scary socialist that are just going to tax and send our economy into ruin," McGrane said.

But after that, the NDP has already rolled out some of its biggest spending promises, such as a national child care program. McGrane said the party will need the rest of the campaign to hope the message of government-subsidized daycare seeps into the consciousness of voters before Oct. 19.