"We must use the necessary measures to catch the tax evaders hiding fortunes in for example Panama with the aim to avoid paying tax in Denmark," Minister for Taxation Karsten Lauritzen said in a statement.
"We cannot be sure of the end result, but everything suggests that it is useful information that the Danish tax authority will now pursue."
The government would pay the source an amount in the "lower millions" of kroner (one million kroner is €134,000, $151,000) for the material, which it estimated could contain information on 320 cases involving between 500 and 600 Danish taxpayers.
The Danish tax authority had already received a "sample" of the data free of charge, the Ministry of Taxation said.
"Against this backdrop it is the tax authority's assessment that the information is sufficiently relevant and valid to initiate tax investigations of a number of the companies and individuals appearing in the material," it said.
Torben Bagge, a lawyer teaching tax law at Aarhus University, noted that Denmark did not "have a tradition of buying information", and cautioned that there was no guarantee that it would be accurate.
Those selling it had "probably not obtained it legally", meaning the government was "in one way or another contributing to illegalities," he told Danish news agency Ritzau.
In April, media outlets published details of murky offshore financial dealings gleaned from 11.5 million leaked documents from a Panamanian law firm -- the so-called "Panama Papers."
The leaks put a host of high-profile politicians, celebrities and sports stars in the hot seat over their assets in tax havens.