Elections Canada has issued political parties and candidates their spending limits for the May 2 election.

The elections agency released the preliminary figures on Wednesday, based on the preliminary list of electors in Canada's 308 ridings.

The amounts political parties can spend in the ridings varies according to the numbers of voters.

The more voters there are in a riding, the more a party can spend to get its candidate elected. So a party running a candidate in Oak Ridges-Markham in Ontario can shell out $132,251 during the campaign, while parties fielding candidates in the riding of Nunavut can spend $14,860.

There are separate spending limits for the political parties and the individual candidates.

Any party that fields a candidate in each of the 308 ridings can spend just more than $21 million in the election campaign, according to Elections Canada. The spending caps on the parties hovered close to $20 million in 2008.

Elections Canada's spending limits have become a contentious issue, considering the so-called "in-and-out " affair dating back to the 2006 election.

The allegations relate to the transfer of $1.3 million between the bank accounts of the national Conservative party and local riding associations in order to buy advertising during the election.

It is alleged that money was transferred to 66 Conservative riding associations, who transferred it back to the national party, which then bought television advertising.

Elections Canada says the campaign cash was used for the advertising and it should have been reported as national expenses. Failing to report the payments, Elections Canada says, means the Conservative Party exceeded the $18.3-million spending limit.

The Conservatives argue they did nothing wrong and the matter is a dispute over an interpretation of the rules.

Several senior Conservatives have been charged with breaking the Elections Act.

Senators Doug Finley and Irving Gerstein, former national party director Michael Donison and former interim executive director Susan Kehoe are facing charges over campaign expenses controversy.

Chief electoral officer Marc Mayrand took the Conservatives to task for what he described as failing to properly report the cost of running two regional campaign offices in Quebec.