The government said 600 police officers had been recruited since 2007
An election pledge to recruit 1,000 additional police officers will be met, according to the Scottish Government.
A study commissioned by ministers estimated there would be more than 17,000 officers in two years.
The Scottish Police Federation, which had been sceptical about the promise, endorsed the report.
The government had been accused of plans to artificially boost numbers by persuading officers to stay beyond their retirement age.
When the SNP came to power there were 16,234 police officers in Scotland. The projection study estimated officer numbers were likely to be between 17,275 and 17,484 by 2011.
Justice Secretary Kenny MacAskill said the forecast figure was a "substantial achievement".
"This study confounds the doom-mongers who said we would not meet our commitment," he said.
The government said 150 additional police officers were recruited in 2007-8, and 450 in 2008-9, and there would be a further 200 officers in both 2009-10 and in 2010-11.
Calum Steele, of the Scottish Police Federation, said the government was delivering the necessary funding for the extra police officers.
He added: "I have seen nothing in the figures which suggests the government is not doing everything in its power to deliver those extra officers.
"I would urge all chief constables to do everything in their powers to ensure the extra police officers demanded by politicians, public and police service alike, are delivered."
The Labour Party accused Mr MacAskill of contradicting what he said a fortnight earlier during a radio interview.
Labour justice spokesman Richard Baker said: "One minute the minister says 'no' the next he says 'yes'. He should act like a justice minister rather than continue with his 'mebbes aye, mebbes naw' approach.
"It's a remarkable coincidence that Mr MacAskill releases this study the day before parliament examines the SNP's police pledge.
"Labour wanted to use that debate to ensure that the SNP recognised the police officer target that Mr MacAskill rejected.
"This announcement means that Mr MacAskill has committed to 17,275 and Labour will continue to remind him of his pledge to the Scottish people."
Conservative justice spokesman Bill Aitken claimed Tory pressure in budget negotiations had secured the extra 1,000 police officers.
"If it had been left to the SNP there would only have been 500 and if it had been up to Labour there would have been none at all," he said.
The study looked at police officer numbers for 31 March, 2008, and factored in projections for recruitment, retirals, and other leavers.