Politicians' pay packets are likely to swell by thousands of dollars after the Tasmanian Industrial Commission recommended a salary increase in line with the Wage Price Index (WPI), despite public sector wages being capped at 2 per cent.

The salary boost has been criticised by the Community and Public Sector Union (CPSU), after the Tasmanian Government last week formally offered public sector workers an annual 2 per cent pay increase for the next three years.

The Tasmanian Industrial Commission has determined that parliamentary salaries should increase in line with WPI, and allowances should increase in line with the Consumer Price Index (CPI).

CPI in Hobart rose by 2.4 per cent over the past financial year, according to the Australian Bureau of Statistics. WPI figures to June are not yet available, but increased by 2.4 per cent in the year to March.

A 2.4 per cent increase would lift the parliamentary base salary by $3,282 to $140,047.

The basic parliamentary salary also increased by 2.4 per cent last year to $136,765, after an increase of 10.5 per cent to $133,560 in 2016.

CPSU general secretary Tom Lynch said Tasmanians would be "shocked" to hear politicians could get a wage increase of more than 2 per cent.

"It's no good for the Government to say the 2 per cent is a fair increase for public sector workers when apparently it's not a fair increase for them," Mr Lynch said.

Unions have called for annual increases of 3 per cent for public sector workers, which the Government says would cost an additional $28 million per year.

Mr Lynch said the Government could have introduced a 2 per cent cap for politicians' wages as well, rather than referring them to the independent Tasmanian Industrial Commission for determination.

"If they think the independent umpire test is the appropriate measure then perhaps they should be referring the wages of public sector workers to the independent umpire," Mr Lynch said.

"We would welcome an opportunity to get before the Industrial Commission and argue why Tasmanian public sector workers deserve wage increases well above the cap that's been imposed by this Government."

A Government spokesman said politicians should not determine their own pay, which was why the Tasmanian Industrial Commission was involved as an "independent umpire".

"The 2 per cent increase for the public sector is affordable, fair, and reasonable and will allow us to employ more nurses, doctors, teachers and frontline workers," the spokesman said.

According to the Tasmanian Industrial Commission's report, no submissions were received opposing the interim salary increase by WPI or allowance increase by CPI.

The increase is for the year to June 2019.

A thorough review of parliamentary salaries and allowances is underway, with a report due in March next year.

Labor was invited to comment.