Treasury Secretary nominee and former Goldman Sachs executive Steven Mnuchin said he would increase the size of the Internal Revenue Service during his confirmation hearing yesterday.

Mnuchin, who has found recent success as a Hollywood producer, said he would also modernize the government agency's technology at his hearing before the Senate Finance Committee.

Mnuchin, 54, said that IRS staff numbers have declined by 30 per cent over the past few years.

He told the hearing: 'Especially for an agency that collects revenues, this is something that I'm concerned about,' the Daily Caller reported.

The number of employees fell by 16 per cent between 2010 and 2015, according to the IRS, and has fallen by 31 per cent since 1997 according to the National Treasury Employees Union.

Its budget in 2016 was $900 million less than its budget in 2011, according to the Government Accountability Office.