Australians continue to pay tribute to Mary MacKillop, soon to be canonised as Australia's first saint.

A website dedicated to McKillop crashed today after a flood of people tried to access it. Anne Walsh, deputy director of Frayne Work, which designed and hosts www.marymackillop.org.au for the Sisters of St Joseph, said the site was down for about 30 minutes.

In another sign of McKillop's popularity, Australia Post will be releasing a second commemorative stamp at the weekend to recognise the saint, who is known to be an avid letter writer. It will be the second stamp released with her image, the first having been issued in 1995 when she was formally beatified.

Earlier this week, National president of United Retail Federation (URF) Scott Driscoll has written to the Pope asking him to petition the federal government to reverse its decision to restrict corporate use of the name of Australia's first saint.

The federal government declared on Monday that MacKillop's name would be protected from the expected onslaught of commercialisation once her sainthood becomes official.

Mr Driscoll said the URF has serious concerns about the government's action, which will amend corporations law so anyone wanting to use a company name implying a connection to Mother Mary will have to seek ministerial approval.

The Vatican City is set to canonise MacKillop on October 17.