Life is about to get much tougher for global corporations that use loopholes to avoid paying taxes.

Finance officials from the world's top 20 economies are about to approve a package of new rules that should help governments crack down on corporate tax avoidance.

Over 60 countries drafted the rules, which will be approved at a G-20 meeting in Lima on Thursday before world leaders give the final sign off next month.

The Organization for Economic Co-operation and Development estimates that loopholes allow companies to dodge as much as $240 billion in taxes per year.

Tax bills may initially rise as a result of the new rules, but over time the architects of the plan expect governments to reduce their tax rates to even things out.

Here are the three key things you need to know about the new initiative:

1. Improved transparency: Multinational firms based in 62 countries will soon be forced to disclose details about their business operations, global subsidiaries, sales, profits, tax payments and employee numbers.

This information will be shared between national tax authorities to ensure companies are being transparent about their operations and tax obligations. This will help countries conduct audits, understand how companies are moving money abroad and levy appropriate taxes.

Currently, it's difficult for countries to track this information, making it easy for companies to stay within the law while avoiding the taxman.

But the information won't be made public, which has angered critics who want even more transparency.

2. Closing the loopholes: The global agreement includes 15 measures to cut down on corporate tax avoidance and ensure countries get their fair share of tax. Even though the measures aren't yet in place, they're already forcing companies to act.

Starbucks (SBUX) and Amazon (AMZN) are both reworking their tax dealings in Europe to satisfy the new rules. Earlier this year, Amazon agreed to pay taxes in several countries across Europe after previously paying taxes solely in Luxembourg.

One of the measures involves countries working together to prevent companies using complex global financial transactions to make taxable income disappear.

About 90 nations will also amend thousands of bilateral treaties to crack down on businesses using "shell companies" in third countries to circumvent tax.

And countries that offer generous tax relief to firms with valuable patents and intellectual property, such as the U.K., have agreed to review their systems to make sure they're fair.

Some notorious tax havens, such as Bermuda and the Cayman Islands, won't sign up to the global deal.

Nevertheless, companies will find it much harder to hide their profits in these countries, said Pascal Saint-Amans, director of tax policy at the OECD, who helped coordinate the new tax rules.

3. Resolving disputes: Officials are well aware that companies may be concerned about being taxed twice in different countries.

Saint-Amans said there will be new "dispute resolution" rules to ensure countries deal with tax problems quickly and fairly. All 62 nations have agreed to resolve tax disputes within a specified timeframe, and they have agreed to be monitored by their peers to ensure they are being fair.