This paper investigates the problem of reliable tone interference estimation from noisy observations. Performing the DFT of time domain observations is a commonly used tone estimation technique. However, the use of one DFT block of frequency domain samples may not yield reliable estimation of tone interference. To solve this problem, we propose to combine multiple DFT blocks of frequency domain observations which are naturally provided in OFDM systems, improving the reliability of tone interference estimation. To this end, a frequency domain DFT is used to process multiple blocks of observations. It is shown that our estimator can achieve the performance close to the Cramer-Rao bound and the conventional DFT-based estimation with much higher complexity.