We present photometric and spectroscopic observations of the Type IIn supernova SN 2019zrk (a.k.a. ZTF 20aacbyec). The SN shows a >~100 day precursor, with a slow rise, followed by a rapid rise to M~-19.2 in the r and g bands. The post-peak light-curve decline is well fitted with an exponential decay with a time scale of ~39 days, but shows prominent undulations, with an amplitude of ~1mag. Both the light curve and spectra are dominated by interaction with a dense circumstellar medium (CSM), probably from previous mass ejections. The spectra evolves from a scattering-dominated Type IIn spectrum to a spectrum with strong P-Cygni absorptions. The expansion velocity is high, ~16000km/s, even in the last spectra. The last spectrum ~110 days after the main eruption reveals no evidence for advanced nucleosynthesis. From analysis of the spectra and light curves we estimate the mass-loss rate to be ~4x10^-2^M_{sun}/yr for a CSM velocity of 100km/s, and a CSM mass of >~1M{sun}_. We find strong similarities of both the precursor, general light curve and spectral evolution with SN 2009ip and similar SNe, although SN 2019zrk displays a brighter peak magnitude. Different scenarios for the nature of the 09ip-class of SNe, based on pulsational pair instability eruptions, wave heating and mergers, are discussed.