Prime Minister Stephen Harper's enlarged cabinet could cost taxpayers an additional $3.9 million in salaries alone for extra ministers and staff.

The total cost of staffing ministerial offices, roughly $24.2 million in salaries, has grown by 19 per cent with last week's shuffle and has jumped 42 per cent since the Tories presented their first cabinet in 2006.

Opposition parties have called the addition of six new cabinet spots a strange message for the government to be sending at a time of economic belt-tightening.

"At a time when the Conservatives are scolding everyone about public spending, and they're saying it's time to tighten our belts, and we might be running a deficit, they should be giving the example," said NDP deputy leader Thomas Mulcair. "But they're not."

The Conservatives had 26 ministers in their initial 2006 cabinet, expanded that to 31 over their first term in office and now have 37.

Mulcair maintained the Conservatives didn't want to fire incompetent ministers, so they demoted them and added unnecessary titles to give a higher profile to MPs in politically key regions.

But the government says the addition of new ministers will save money in the long run.

Harper spokesman Kory Teneycke says the extra ministers will provide additional political oversight of departmental budgets.

They will also help the government implement its agenda, with the No. 1 item on that agenda being the ongoing global economic crisis, Teneycke said.

"Clearly, this government is going to be focused heavily on the economy," he said. "I don't think having more oversight by elected officials is a bad thing. It's a very good thing."

Salaries under the microscope

The dollar amounts cited above were calculated by the Canadian Press, using the salaries of employees in the offices of ministers of state, more commonly known as junior ministers.

The calculations are based on employees earning the highest possible salary within their pay grade. On the other hand, the numbers exclude the significantly higher salaries paid to top employees in senior ministers' offices, and they omit other expenses not related to salary.

Each new cabinet spot carries a variety of extra costs: a salary hike for the minister, additional staff, a car and driver, rides on government planes and bigger travel expenses.

Without taking into account the car, the plane rides, or the travel expenses, any new minister's office could easily cost more than $600,000 in salary commitments.

Ministers make $74,400 more than regular MPs. And the salaries for their staff are spelled out in the Treasury Board Secretariat's policies and Guidelines for Ministers' Offices.

The four secretaries of state in the previous cabinet — a position that has now been elevated to the higher rank of minister of state — averaged eight staff members each.

Adding the maximum salary allowed for a chief of staff to a minister of state (the pay range is $77,490-$110,700), a senior special assistant ($63,294-$90,420), a special assistant, five support staff (for a total of eight staffers) and tossing in the minister's $74,400 pay increase, the cost of salaries in a minister of state's office is $653,674.

Overall, the extra six cabinet members would cost an extra $3.92 million in salaries, which comes out of the federal government's $240 billion annual budget.