President Donald Trump's son-in-law Jared Kushner paid almost no income tax for years

Jared Kushner, the son-in-law of US President Donald Trump and senior White House advisor, paid almost no federal income tax for years.

Only a week after The New York Times revealed President's Trump 'self-made' wealth was the result of dubious tax schemes and handouts from his father's real estate empire, his son-in-law has found himself at the middle of a tax scandal.

The Times has reviewed confidential financial documents which suggest Mr Kushner used a common tax-minimising scheme to create the illusion he was losing money.

But that was only on paper, and Mr Kushner was instead increasing his net worth - estimated to be nearly NZ$500 million - by buying real estate.

The losses were driven by depreciation, a tax benefit allowing real estate investors to deduct a portion of the cost of their buildings from their taxable income every year.

An example of this was in 2015, when Mr Kushner took home US$1.7 million in salary and investment gains, but his earnings were swamped by US$8.3 million in losses because of "significant depreciation" on his real estate.

While the tax manoeuvre isn't illegal and is meant to protect developers from their investments being whittled away from wear and tear, the Times describe the allowance as a "lucrative giveaway to developers like Mr Trump and Mr Kushner".

The law assumes investment buildings lose value every year, but as is common in real estate, they may often gain value.

A spokesperson for Mr Kushner has said the man who is married to Ivanka Trump has "paid all taxes due".

Peter Mirijanian, a spokesperson for Mr Kushner's lawyer, Abbe Lowell, said the documents the Times reviewed had been "obtained in violation of the law and standard business confidentiality agreements".

The documents totalled more than 40 pages, describing business dealings, expenses and earnings from 2009 to 2016. They were created in cooperation with Mr Kushner as part of a review of his finances by an institution considering lending him money.