The change, being organised by US quango, the Internet Corporation for Assigned Names and Numbers (ICANN), involves the introduction of more specific suffixes on web addresses.
For example, drinks giant Pepsi could apply to have websites at .pepsi or .tropicana, rather than .com, while car giant Ford could get .ford.
Interested parties are allowed to request up to 50 web address endings, and ICANN will publish application details on April 30.
ICAAN has already confirmed that 839 users signed up to take part in the process in March, but these firms, brands and organisations still have to meet tonight's deadline.
US search giant Google is understood to be among the companies to have paid the $185,000 (£116,355) fee required to take part in the process.
Cannon has also said it will take part, while Nominet, the organisation that co-ordinates the .uk domain names, confirmed that it is applying for .wales and .cymru domains.
Maintaining the new domain name suffixes will cost at least £25,000 annually, so only major organisations are expected to apply.
There has been concern that the change could cause problems in cases where brands have the same name, such as Anheuser-Busch InBev and Budejovicky Budvar both holding the Budweiser trademark.
ICAAN urged companies to try and negotiate a deal in such cases, but said that it would hold an auction of the domain as a "last resort".
Generic extensions, such as ".web", are also available and major demand is expected to trigger an auction among interested parties.
The change has been planned for several years, but they have also attracted controversy.
Some critics have claimed that the move could encourage "cyber squatting", in which web addresses are speculatively acquired in the hope of brands paying big to win them back, or the addresses being used to parasite legitimate web traffic.
Last November, a group of 87 business associations and companies, including Adobe, Dell and Samsung, also signed a petition sent to the US Department of Commerce protesting that the change will cause "excessive cost and harm to brand owners".
But supporters of the move have said that it could help improve security online, such as internet banking users only visiting confirmed bank websites with official suffixes rather than fake sites.
In response to the criticism, an ICANN spokesman told the BBC: "This programme is the result of six years of careful study and deliberation which involved more than 2,400 public comments and dozens of public comment periods.
"It was neither hasty nor ill conceived."
It is expected to take at least 18 months before the first new web address suffixes goes live.
This follows a move to licence .xxx domain suffixes for adult entertainment and pornographic websites, a move to create a 'virtual red light district' that caused equal controversy.
> Sir Richard Branson wins .xxx domain dispute