Pretoria - The government will soon implement stringent measures to clamp down on tax defaulters, Finance Minister Pravin Gordhan said on Sunday.Launching the SA Revenue Service (Sars) compliance programme in Pretoria, Gordhan said that although overall tax compliance has improved, the trends require constant monitoring."Sars will continue to widen the base of people who are within the tax bracket through constant innovations to ensure that all who should be part of the tax system are part of it," he said."Research has identified particular areas in our economy and in our tax system posing higher risks of non-compliance."Both small and major players in the construction industry were among the major defaulters, said Sars commissioner Oupa Magashula."Those people who are not compliant, we know who these people are (and are) going to do something about it," he said."The message today is: talk to us before we talk to you. If we call you, be assured that you will pay the penalties," said Magashula.