The Government's annual spending on advertising rocketed by 70 per cent to a record £192.4m before the general election.

Conservatives demanded an investigation by public finance watchdogs last night into what they called "a pre-election splurge" at the taxpayers' expense, designed to boost Labour's electoral prospects.

The figures released yesterday show the Government was Britain's second biggest advertiser in the financial year to March, just behind Unilever, which spent £197.9m, and ahead of Procter & Gamble on £132.7m. The data reflects a hike in government advertising in the first quarter of this year – when Tony Blair planned to call an election in May. Whitehall departments spent £62.8m, making the Government the country's biggest advertising spender, well ahead of second-placed Unilever on £34.3m.

In the year up to the 1997 election, the Tory government spent £69.3m. Under Mr Blair, the budget rose from £59m in his first year to £105.4m in year two and £113.4m in his third year. That has been dwarfed by the £192.4m spent last year.

The departments with the biggest rises included Education and Employment (up from £20.4m to £36.9m); Health (up from £17.9m to £26.2m); the Inland Revenue (up from £15m to £21m) and Social Security (up from £8.1m to £20.9m).

The Tories described several Whitehall campaigns as a waste of money, claiming a television blitz to tell pensioners of the minimum income guarantee cost £150 for each person receiving the benefit and that an anti-fraud campaign only served to encourage benefit fiddles.

Another controversial campaign was one by the Department of Trade and Industry to publicise new rights for workers to take paid holiday leave. This cost £2.5m and some civil servants are believed to have been uneasy at the use of television commercials.

Andrew Lansley, the Opposition spokesman on Cabinet Office issues, has written to Sir John Bourn, the Auditor General, asking him to investigate the campaigns. He said the publicity should have been paid for by the Labour Party rather than taxpayers.

Mr Lansley said: "Ministers clearly took decisions designed to create the impression of positive activity in order to disguise their failure to deliver and encourage the electorate to give them a second chance."

David Willetts, the Opposition spokesman on work and pensions, will ask the Commons Public Accounts Committee to investigate the increase in spending and will urge the Cabinet Office to bring in guidelines to prevent a repeat ahead of future elections.

He said: "We need much greater controls and policing to stop such a re-election splurge in government advertising. People do need to know their rights but is it very suspicious why the Government wanted to do it just before the election."

A Cabinet Office spokesman said: "Advertising or other paid means of communication are only used when communication is an essential part of implementing policy or programmes. These are important public information campaigns, such as public-sector recruitment, anti drink-driving and raising awareness of how to tackle car-crime. There are strict rules to ensure they are in no way party political."

The Tories claim Britain is unusual in having the Government as one of its biggest advertisers. But Labour insists the trend was established by the Tories, noting that spending broke the £100m-a-year barrier under Margaret Thatcher, who ran campaigns to promote "enterprise culture" and schemes for the jobless.