Aims. In this paper, we aim to study the main properties and luminosity function (LF) of the [OII]3727 emitters detected in the OTELO survey in order to characterise the star formation processes in low-mass galaxies at z similar to 1.43 and to constrain the faint-end of the LF.Methods. Here, we describe the selection method and analysis of the emitters obtained from narrow-band scanning techniques. In addition, we present several relevant properties of the emitters and discuss the selection biases and uncertainties in the determination of the LF and the star formation rate density (SFRD).Results. We confirmed a total of 60 sources from a preliminary list of 332 candidates as [OII]3727 emitters. Approximately 93% of the emitters have masses in the range of 10(8)(*)) of the LF and explains the discrepancy of our results when compared with those obtained from surveys of much larger volumes. However, we are able to determine the faint-end slope of the LF, namely, alpha=-1.42 +/- 0.06, by sampling the LF down to similar to 1 dex lower than in previous works. We present our calculation of the SFRD of our sample and compare it to the value obtained in previous studies from the literature.