OTTAWA — The NDP says 27 senators appointed by Prime Minister Stephen Harper over the past year could cost Canadian taxpayers $177 million over the life of their sinecure.

The analysis released by New Democrat Peter Stoffer found that Senate travel and office expenses have more than doubled in the past 14 years, climbing three times faster than overall government spending.

Average office and travel expenses for sitting senators in 2008-09 amounted to almost $197,000 each.

Using salary calculations plus average expense claims, the NDP found that the 27 most recent Conservatives appointed to the upper chamber will eat up almost $85 million in salary and almost $92 million in expenses if they sit until mandatory retirement at age 75.

While Harper says his newly appointed Tory senators have promised to retire after eight years, Stoffer says Harper may no longer be prime minister then and there is nothing legally compelling the senators to step down.

Among the new Tories in the upper chamber, Senator Mike Duffy alone booked more than $44,000 in travel expenses despite sitting for just three months at the end of the 2008-09 fiscal year.

The former broadcaster has been a regular at Conservative fundraisers across Canada this year.