However, the Australian Communications Authority said the matter would be "discussed" during a government review next year of the operation of Australia's Spam Act.
Howard has admitted he had hired his son's company, Net Harbour, to distribute e-mails containing promotional Liberal Party electoral material to voters in his electorate of Bennelong.
ACA anti-spam manager Anthony Wing pointed out that the Spam Act clearly only covers commercial spam and "does not cover non-commercial ones such as charities and election [materials] by registered political parties".
"As far as I'm aware, it is purely electoral material and there are no restrictions under the Spam Act on electoral materials," Wing said.
The Sydney Morning Herald newspaper quoted one recipient of the e-mails -- who resides outside the Bennelong electorate -- as being angry and concerned about how Net Harbour got hold of her address.
Wing said if further complaints came in from recipients of the unsolicited e-mails, the regulator would take a look at the contents of the e-mail. However, the ACA's hands are tied, he said, and the organisation will not be able to investigate the matter in the context of any breaches of the Spam Act.
"We apply the Spam Act as it stands at the moment," he said.
John Howard told ABC Radio in Hobart today he had personally funded the campaign being spread by Net Harbour, but would not disclose how much it cost.
"That is my business because it's not public money, it's private Howard money and I don't intend to disclose that because it's a private matter," Howard told listeners. "It is being sent out in my name as the Member for Bennelong".
Net Harbour refused to make any comment about the issue.
Shadow minister for ICT, Kate Lundy, said the Prime Minister had breached the "spirit" of the anti-spam law and described the situation as a case of double standards.
"The Prime Minister has breached the spirit, if not the letter of anti-spam laws. John Howard's government banned commercial spamming this year, but then the Prime Minister goes ahead and spams the public for political benefit -- this is a clear case of double standards," Lundy said.
Lundy believes the ACA should investigate Howard's use of spam. However, she added that it was questionable whether engaging a commercial company to send spam breached the Spam Act.
"Mr Howard obviously thinks he is either above the law or is cynically exploiting a loophole against the spirit and principle of a law his own government has been touting as evidence of its social responsibility for the past year," she said.
An announcement of a federal election date is imminent with speculation rife after John Howard's plans to visit Canberra this weekend. While Howard has declined to comment about what he may do on Saturday or Sunday, pundits are speculating that his itinerary may include a visit to Government House to advise the governor-general of his plans to hold a federal election.