Inflation measured by the wholesale price index -- the most closely watched cost-of-living monitor -- accelerated to 6.11 percent for the week ended January 20 from 5.95 percent the previous week and 4.24 percent a year earlier, the government said.

The rate had reached 6.12 percent in the week ended January 6, the highest since December 2004 when it stood at 6.56 percent, prompting the Reserve Bank of India to raise its key short-term borrowing rate by a quarter percentage point on Wednesday to 7.5 percent.

The rate is hovering above the 5.5 percent tolerance limit set by the Reserve Bank, which has been using a variety of tools to fight inflation since it began a tightening cycle in late 2004.

In December, it boosted the amount of money that banks must keep with the central bank, raising the cash reserve ratio by 50 basis points to 5.5 percent in a bid to suck out cash from the banking system and tame credit growth that's fuelling economic expansion.

The government has also cut customs duties on cooking oil, cement and other products in a bid to lower prices. Such efforts will take time to work, the Press Trust of India cited unnamed government officials as saying Friday.